\ 

LIBRARY 

OF   THE 

UNIVERSITY  OF  CALIFORNIA. 
Class 


PRODUCTION    AND 
PROPERTIES   OF  ZINC 


A  treatise  on  the  occurrence  and  distribution  of  zinc 
ore,  the  commercial  and  technical  conditions 
affecting  the  production  of  spelter,  its  chem- 
ical and  physical  properties  and  uses  in 
the  arts,  together  with  a  historical  and 
statistical  review  of  the  industry 


By 

WALTER    RENTON    INGALLS 

h 


OF  THE 

{   UNIVERSITY 

,C4U£!L.,i^  J    FIRST 


NEW      YORK      AND      LONDO 


The    Engineering   and    Mining  Journal 


1902 


-  /  ' 


Copyright,    1902, 

by 

The  Engineering  and  Mining  Journal. 


PREFACE. 

This  book  was  undertaken  originally  as  the  introductory  portion  of  a 
treatise  on  the  metallurgy  of  zinc.  Upon  the  completion  of  the  latter,  how- 
ever,, it  appeared  advisable  for  various  reasons  to  limit  it  to  a  consideration 
of  the  purely  technical  questions  involved  in  the  extraction  of  zinc  from 
its  ores,  or  rather  the  concentrated  products  which  are  delivered  by  the 
miners  for  smelting.  Although  a  knowledge  of  the  physical  and  chemical 
properties  of  the  metal,  the  occurrence  of  its  ores,  and  the  conditions  which 
affect  the  markets  is  of  importance  to  the  smelter,  it  is  equally  of  impor- 
tance to  the  miner  and  trader.  It  was  thought  therefore  that  a  collection 
of  the  general  commercial  and  technical  data  of  the  metal  in  a  special 
treatise  devoted  solely  to  it  would  be  useful  to  those  who  are  engaged  in  the 
industry  in  the  various  ways,  and  with  that  in  view  the  present  book  was 
prepared  upon  a  considerable  enlargement  of  the  original  plan. 

It  has  been  the  aim  in  this  book  to  present  a  comprehensive  review  of  the 
world's  resources  of  zinc  ore,  the  conditions  under  which  it  is  produced,  the 
concentration  of  the  crude  ore  into  a  product  suitable  for  smelting,  and  a 
summary  of  the  statistics  of  the  industry  from  the  earliest  records  down  to 
the  present  time.  The  extent  into  which  the  subjects  of  ore  supply  and 
mechanical  concentration  of  the  crude  ore  have  been  entered  into  is  due  to 
their  especial  interest  in  this  industry.  There  is  perhaps  no  other  impor- 
tant branch  of  metallurgy  in  which  the  exigencies  of  the  smelting  process 
impose  such  narrow  limits  as  to  the  grade  and  character  of  the  ore  and 
make  the  preliminary  preparation  of  the  ore  a  matter  of  such  great  concern 
as  in  the  metallurgy  of  zinc. 

In  concluding  this  preface,  I  desire  to  make  acknowledgment  to  all  who 
have  aided  me  in  the  preparation  of  the  book,  and  especially  to  Mr.  E.  C. 
Moxham  for  notes  as  to  zinc  mining  in  Virginia,  and  Professor  H.  0. 
Hofman  for  permission  to  reproduce  illustrations  from  his  valuable  treatise 
on  the  Metallurgy  of  Lead ;  also  to  the  American  Metal  Co.  for  its  statistical 
publications,  and  the  Robins  Conveying  Belt  Co.,  the  Wetherill  Separating 
Co.  and  Mr.  W.  P.  Cleveland  for  illustrations  supplied  by  them. 

WALTER  RENTON  INGALLS. 

Lynn,  Mass.,  July,  1902. 

in 

111730 


CONTENTS. 

PAGES 

CHAPTER  I. — HISTORY  OF  THE  ZINC  INDUSTRY 1-15 

Zinc  in  Ancient  Times,  1.  In  the  Middle  Ages,  2.  Introduction  of  Zinc 
Smelting  into  England  from  China,  3.  Beginning  of  Zinc  Smelting  in  Bel- 
gium, 4.  Carinthia,  6.  Great  Britain,  7.  (Silesia,  7.  United  States,  13. 

CHAPTER  II. — PRESENT   ECONOMIC   CONDITIONS 16-47 

Rank  of  Various  Countries  as  Zinc  Producers,  16.  List  of  European 
Zinc  Smelters,  17.  List  of  American  Zinc  Smelters,  20.  Ore  Supply,  22. 
Systems  of  Zinc  Smelting,  22.  Belgium,  25.  Coal  Resources  of  Belgium, 
25.  Cost  of  Coal  in  Belgium,  2.7.  Cost  of  Fire  Clay,  28.  Cost  of  Labor, 
28.  Statistics  of  the  Belgian  Zinc  Industry,  28.  Character  of  Ore 
Smelted,  29.  France,.  30.  Germany,  30.  Rhenish  Prussia  and  West- 
phalia, 30.  Coal  Resources,  31.  Labor,  Ore  and  Refractory  Material,  31. 
Silesia,  32.  Coal  Resources  of  Silesia,  32.  Cost  of  Coal,  33.  Labor,  Ore 
and  Refractory  Material,  33.  Great  Britain,  34.  Coal  and  Fire  Clay,  34. 
Wages,  34.  Furnaces  Employed,  34.  Greece,  35.  Cost  of  Producing  Ore 
at  Laurium,  35.  Italy,  36.  Netherlands,  36.  Russia,  36.  Spain,  37. 
United  States,  37.  Eastern  Districts,  37.  Western  Districts,  38.  Tardy 
Development  of  Kansas-Missouri  Zinc  Smelting  Practice,  39.  Rise  of  the 
Natural  Gas  Smelteries  in  Kansas,  40.  Coal  Resources  of  the  United 
States,  41.  Cost  of  Coal,  42.  Natural  Gas  Supply,  43.  The  lola  Field, 
43.  Cost  of  Gas,  44.  Character  of  the  Zinc  Ore  Smelted  in  the  United 
States,  45.  Cost  of  Refractory  Material,  46.  Wages  of  Labor,  46.  Cen- 
tralization of  the  American  Production  and  Consumption  of  Spelter,  46. 

CHAPTER  III.— USES  OF  ZINC  AND  ZINC  PRODUCTS 48-62 

Itemization  of  the  Consumption  of  Spelter,  48.  Sheet  Zinc,  49.  Use  as 
Roofing  Material,  50.  Dimensions  and  Weight  of  Zinc  Sheets,  50.  Sheet 
Zinc  Gauges,  51.  Directions  for  Laying  Sheet  Zinc  Roofs,  52.  Advan- 
tages of  Zinc  Roofs,  52.  Methods  of  Roofing  with  Sheet  Zinc,  53.  Cost 
of  Roofing  with  Zinc,  54.  Comparative  Cost  of  Roofs  of  Various  Mate- 
rials under  American  Conditions,  54.  Employment  of  Zinc  Plates  to 
Prevent  Boiler  Corrosion,  55.  Consumption  of  Sheet  Zinc  in  the  Cyanide 
Process  of  Gold  Extraction,  56.  Miscellaneous  Uses  of  Sheet  Zinc,  57. 
Zinc  Castings,  58.  Consumption  of  Zinc  in  Brass  Making,  58.  Use  of 
Zinc  for  Desilverizing  Lead,  59.  Use  of  Zinc  in  Galvanizing,  60.  Zinc 
Dust,  60.  Zinc  White,  61.  Other  Uses  of  Zinc,  61.  Limitation  of  the 
Use  of  Zinc,  61. 

CHAPTER  IV.— STATISTICS  OF  PRODUCTION  AND  PRICES 63-92 

Reports  of  Various  Statisticians,  63.  Production  of  Zinc  Ore  in  Europe 
and  Australia  from  1840  to  1900.  64.  Production  of  Blende  and  Calamine 
in  Belgium,  66.  Imports  and  Exports  of  France,  66.  Production  of  the 
Zinc  Mines  and  Smelteries  of  Upper  Silesia  from  1861  to  1900,  67. 
Imports  and  Exports  of  Germany,  68.  Exports  of  Zinc  Ore  from  Spain, 


VI  CONTENTS. 


68.  Exports  of  Zinc  Ore  from  New  South  Wales,  69.  Production  of 
Zinc  Ore  in  the  United  States,  69.  Exports  of  Zinc  Ore  from  the  United 
States,  70.  The  World's  Production  of  Zinc  from  1845  to  1901,  71. 
Comparison  of  Statistics  of  Production,  73.  Production  of  Spelter  in  the 
United  States,  74.  Production  of  Zinc  Oxide  in  the  United  States,  75. 
Statistics  of  Consumption,  75.  Consumption  of  Zinc  in  Austria-Hungary, 
77.  In  Belgium,  77.  In  France,  77.  Movement  of  Sheet  Zinc  from  and 
into  France,  78.  Consumption  of  Zinc  in  Germany,  78.  Movement  of 
Sheet  Zinc  from  and  into  Germany,  78.  Consumption  of  Zinc  in  Great 
Britain,  78.  Movement  of  Sheet  Zinc  from  and  into  Great  Britain,  78. 
Consumption  of  Zinc  in  Italy,  79.  In  Russia,  79.  In  Spain,  79.  In  the 
United  States,  80.  The  World's  Consumption  of  Zinc,  80.  Consump- 
tion of  Zinc  White  in  the  United  States,  81.  Statistics  of  Price,  82. 
Average  Monthly  Price  of  Prime  Western  Spelter  at  New  York 
from  1875  to  1901,  83.  Average  Annual  Price  of  Ordinary  Silesian 
Spelter  at  London  from  1869  to  1901,  83.  Average  Annual  Price 
of  English  Spelter  at  London  from  1872  to  1899,  84.  Average  Yearly 
Price  of  Spelter  in  the  Principal  Markets  in  Germany  from  1879  to  1900, 
84.  Equivalent  Prices  of  Spelter  in  Pounds  Sterling  per  2240  lb.,  Marks 
per  100  Kg.,  and  U.  S.  Currency  per  100  lb.,  84.  Average  Annual  Price 
of  Spelter  in  Various  Markets,  Reduced  to  Cents  per  Pound,  86.  Aver- 
age Price  of  Spelter  for  Decennial  Periods,  87.  Historical  Review  of  Fluc- 
tuations in  the  Price  of  Spelter,  87.  Average  Price  of  Zinc  Blende  Ore  at 
Joplin,  Mo.,  89.  Production  of  Sheet  Zinc  in  Belgium,  Silesia  and  Spain, 
90.  Production  of  Zinc  Sulphate  in  Germany,  91.  Production  of  Spelter 
and  Zinc  Dust  in  Upper  Silesia  by  Works,  91.  Statistics  of  the  Soci6t£ 
Anonyme  de  la  Vieille  Montagne,  92. 

CHAPTER  V.— ANALYSIS  OF  ZINC  ORES  AND  PRODUCTS 93-132 

Determination  of  Zinc,  93.  Potassium  Ferrocyanide  Method,  94.  Von 
Schulz  and  Low  Process  of  1892,  95.  Of  1900,  99.  Stone's  Process  for 
the  Analysis  of  Manganiferous  Zinc  Ore,  101.  Additional  Notes  Respect- 
ing the  Ferrocyanide  Method,  103.  Sodium  Sulphide  Method,  104. 
Other  Methods,  108.  Titration  with  Standard  Acid,  108.  Titration  with 
Standard  Alkali,  108.  Titration  with  Sodium  Thiosulphate,  109.  Electro- 
lytic Assay,  110.  Gravimetric  Method  by  Precipitation  as  Sulphide,  110. 
Determination  of  Cadmium,  111.  Determination  of  Lead,  112.  Am- 
monium Molybdate  Method,  112.  Potassium  Permanganate  Method, 
113.  Potassium  Ferrocyanide  Method,  115.  Determination  of  Iron,  115. 
Determination  of  Lime  and  Magnesia,  118.  ^Determination  of  Sulphur 
and  Sulphuric  Acid,  121.  Gravimetric  Methods,  121.  Fusion  with  Potas- 
sium Hydrate,  121.  Digestion  with  Nitric  Acid,  122.  Volumetric  Meth- 
ods, 123.  Furman's  Process,  123.  Andrew's  Process,  124.  Special  An- 
alytical Methods,  125.  Determination  of  Zinc  in  Alloys,  125.  Analysis 
of  Spelter,  126.  Valuation  of  Zinc  Dust,  128.  Determination  of  Sul- 
phates and  Sulphides  in  Roasted  Ore,  130.  Determination  of  Sulphurous 
Acid  in  Roasting  Furnace  Gas,  130. 

CHAPTER  VI.— PROPERTIES  OF  ZINC  AND  ITS  ALLOYS 133-147 

Relation  of  Zinc  to  Other  Elements,  133.  Atomic  Weight  of  Zinc,  133. 
Specific  Gravity,  134.  Melting,  Boiling  and  Ignition  Points,  134.  Crys- 
tallization, 135.  Ductility,  Malleability  and  Hardness,  135.  Thermal 
and  Electrical  Conductivity,  136.  Tensile  Strength,  136.  Chemical 
Properties,  137.  Impurities  Occurring  in  Commercial  Zinc  and  Their 
Effect,  138.  Lead,  138.  Iron,  139.  Cadmium,  140.  Copper  and  Tin, 
140.  Rare  Metals,  140.  Arsenic  and  Antimony,  140.  Sulphur  and 
Carbon,  141.  Chlorine,  141.  Oxygen,  141.  Zinc  Alloys,  141.  Alumi- 
num and  Zinc,  142.  Antimony  and  Zinc,  143.  Bismuth  and  Zinc,  143. 


CONTENTS.  Vll 


Copper  and  Zinc,  144.  Gold  and  Zinc,  144.  Iron  and  Zinc,  144.  Lead 
and  Zinc,  145.  Mercury  and  Zinc,  145.  Silver  and  Zinc,  145.  Tin  and 
Zinc,  145.  Other  Binary  Alloys,  146.  Complex  Alloys,  146. 

CHAPTER  VII.— CHEMISTBY  OF  THE  COMPOUNDS  OF  ZINC 148-168 

Sulphide,  148.  Sulphites,  152.  Sulphates,  153.  Oxides,  156.  Hy- 
droxide, 160.  Carbonates,  160.  Chromate,  162.  Silicates,  1621  Alumi- 
nate,  163.  Ferrate,  163.  Chlorides,  164.  Bromides,  166.  Iodides,  166. 
Fluorides,  167.  Heat  of  Formation  of  Various  Compounds  of  Zinc,  167. 

CHAPTER  VIII.— THE  ORES  OF  ZINC 169-177 

Nomenclature  of  Zinc  Ores,  169.  Mineralogical  Varieties,  171.  Blende, 
171.  Voltzite,  173.  Goslarite,  173.  Smithsonite,  173.  Franklinite,  174. 
Zinkite,  175.  Hydrozinkite,  175.  Willemite,  176.  Hemimorphite,  176. 
Native  Zinc,  177. 

CHAPTER  IX.— OCCURRENCE  OF  ZINC  ORE  IN  NORTH  AMERICA 178-206 

Zinc  Ore  Deposits  of  the  United  States,  179.  Arkansas,  179.  Colorado, 
181.  Kentucky,  182.  Missouri  and  Kansas,  183.  Nature  of  the  Ore 
Deposits,  183.  Grade  of  the  Ore,  185.  Mining  Conditions,  188.  Litera- 
ture, 190.  New  Jersey,  190.  Geology  of  the  Ore  Deposits,  190.  Char- 
acter of  the  Ore,  192.  Exploitation  of  the  Mines,  193.  New  Mexico,  194. 
Pennsylvania,  195.  Friedensville,  195.  Character  of  the  Deposits,  195. 
Character  of  the  Ore,  196.  Tennessee,  197.  Mossy  Creek  and  New  Mar- 
ket, 197.  Straight  Creek,  198.  Lead  Mine  Bend,  199.  Mining  Con- 
ditions, 200.  Utah,  200.  Virginia,  200.  The  Bertha  Mines,  201.  Char- 
acter of  the  Ore,  201.  Method  of  Mining,  202.  The  Clark  Mine,  202. 
Wisconsin  and  Iowa,  203.  Geology,  203.  Kinds  of  Ore,  204.  Mining 
Conditions,  204.  Occurrence  of  Zinc  Ore  in  Canada  and  Mexico,  205. 

CHAPTER    X. — OCCURRENCES    OF    ZINC    ORE    IN    EUROPE,    AFBICA    AND 

AUSTRALIA 207-231 

Zinc  Ore  Deposits  of  Europe,  207.  Austria,  208.  Belgium  and  Mores- 
net,  209.  Bleyberg,  209.  Vieille  Montagne,  209  Welkenrodt,  210. 
Nouvelle,  Montagne,  210.  Corphalie,  210.  Philippeville,  210.  France, 
210.  Angoumois,  210.  Brittany,  210.  Dauphiny,  211.  Gascony,  211. 
Languedoc,  211.  Provence,  212.  Germany,  212.  Baden,  212.  Hanover, 
212.  The  Upper  and  Lower  Harz,  212.  Nassau,  213.  Rhenish  Prussia, 
214.  Saxony,  214.  Upper  Silesia,  215.  Geology,  215.  Kinds  of  Ore, 
217.  Mining  Conditions,  219.  Westphalia,  220.  Great  Britain,  220. 
England,  220.  Wales,  221.  Greece,  221.  Italy,  223.  Sardinia,  223. 
The  Malfidano  Mines,  223.  The  Monteponi  Mines,  223.  The  Montevec- 
chio  Mine,  224.  Composition  of  Sardinian  Ore,  224.  Zinc  Deposits  of 
the  Italian  Mainland,  225.  Russia,  225.  The  Caucasus,  225.  Poland, 
225.  Spain,  226.  Murcia,  226.  Santander,  226.  Teruel,  226.  Sweden, 
227.  Turkey,  227.  Zinc  Ore  Deposits  of  Africa,  228.  Algeria,  228. 
Tunis,  228.  Zinc  Ore  Deposits  of  Australia,  229.  Broken  Hill,  229.  New 
Caledonia,  231.  Tasmania,  231. 

CHAPTER  XI. — MECHANICAL  CONCENTRATION  OF  ZINC  ORES 232-289 

Objects  and  Limitations  of  Concentration,  232.  Manual  Selection,  or 
Hand  Sorting,  233.  Methods  of  Breaking  the  Ore,  234.  Proportion  of 
Fines  Made,  234.  Cost  of  Breaking,  235.  Spalling,  235.  Culling,  237. 
Stationary  Tables,  237.  Revolving  Tables,  237.  Endless  Belt  Tables, 
240.  Efficiency  in  Hand  Sorting,  240.  Gravity  Concentration,  241.  Car- 
dinal Principles,  242.  Crushing,  242.  Screening,  243.  Jigging,  243. 
Slime  Washing,  243.  General  Arrangement  of  Plants,  244.  Specific 


Vlll  CONTENTS. 

PAGES 

Gravity  of  Zinc  and  Associated  Minerals,  244.  Ore  Dressing  in  Upper 
Silesia,  244.  The  Neue  Helene  Mill,  245.  Ore  Dressing  in  Missouri  and 
Kansas,  246.  Method  of  Milling,  246.  Cost  of  Treatment,  248.  Loss  of 
Mineral,  249.  Total  Cost  of  Production,  252.  Relation  Between  Ore 
Dressing  and  Smelting,  253.  Separation  of  Blende  and  Pyrites,  255. 
Practice  in  Wisconsin,  256.  Practice  at  Iserlohn,  257.  Separation  of 
Blende  from  Other  Minerals  by  Sifting,  257.  Practice  at  Lintorf,  257. 
Practice  at  Oberlahnstein,  258,.  The  Heusschen  Process,  258.  Magnetic 
Separation,  258.  Separation  of  Strongly  Magnetic  Minerals,  259.  Con- 
version of  Iron  Bisulphide  into  Magnetic  Sulphide,  259.  Conversion  of 
Ferric  Oxide  into  Magnetic  Oxide,  259.  Practice  at  Monteponi,  260.  The 
Ferraris  Magnetic  Separator,  261.  Separation  of  Siderite  and  Blende, 
262.  Practice  at  Friedrichssegen,  262.  Calcining  Furnace  Used  at  Fried- 
richssegen,  265.  The  Wenstrom  Separator,  266.  Separation  of  Frank- 
Unite  and  Willemite,  267.  Separation  of  Feebly  Magnetic  Minerals,  268. 
The  Wetherill  Separator,  269.  Theory  of  the  Wetherill  System,  274. 
Conditions  of  Practical  Application,  276\  Practical  Results  of  the  Weth- 
erill System,  276.  Austin ville,  Va.,  276.  Mine  Hill  and  Franklin  Fur- 
nace, N.  J.,  277.  Joplin,  Mo.,  278.  Denver,  Colo.,  278.  Lohmannsfeld, 
Germany,  279.  Broken  Hill,  N.  S.  W.,  284.  La  Trieuse  Separator,  285. 
The  Cleveland-Knowles  Magnetic  Separator,  285. 

CHAPTER  XII.— CAMPLING  AND  VALUATION  OF   ORES 290-313 

Introductory,  290.  Sampling,  292.  Theory,  292.  Degree  of  Crushing 
Required,  293.  Sampling  by  Hand,  294.  Sample  Grinder,  294.  Grid,  or 
Riffle,  Sampler,  295.  Jones'  Sampler,  296.  Quartering,  296.  Mechanical 
Sampling,  298.  The  Vezin  Sampler,  298.  Installation  of  Vezin  Sam- 
plers, 299.  Arrangement  of  Mechanical  Samplers,  299.  Determination 
of  Moisture,  301.  Ore  Sampling  in  Europe,  302.  Valuation  of  Zinc  Ores, 
303.  Custom  of  the  Joplin  District,  303.  Sliding  Scales,  304.  Value  of 
Lead  and  Silver  Bearing  Zinc  Ores,  312.  Deduction  in  Value  on  Account 
of  Iron,  312.  Conclusion,  312. 


LIST  OF  ILLUSTRATIONS. 

FIGURES  PAGE 

1.  Map  of  Portions   of  Belgium,   France,   Holland   and   Rhenish   Prussia, 

Showing  Location  of  Zinc  Smelteries 26 

2.  Zinc  Smeltery  at  Pittsburg,  Kail Facing  38 

3.  Works  No.  2  of  the  Cherokee-Lanyon  Spelter  Co.,  at  Pittsburg,  Kan.    Facing  38 

4.  Zinc  Smeltery  at  Cherokee,  Kan Facing  40 

5.  Zinc  Smeltery  at  Nevada,  Mo Facing  40 

6-7.     Works  of  the  Cherokee-Lanyon  Spelter  Co.,  near  Tola,  Kan Facing  44 

8.  Apparatus  for  the  Determination  of  Sulphurous  Acid 131 

9.  Map  of  Portions   of   Missouri   and   Kansas,   Showing   Location   of   Zinc 

Mines    and    Smelteries 184 

10-12.     Typical  Ore  Deposit  near  Webb  City,  Mo 186,  187,  189 

13.     Map  of  Franklinite  Deposit  at  Franklin  Furnace,  N.  J 191 

14-15.     Transverse  Sections  of  Zinc  Ore  Deposit  at  Franklin  Furnace,  N.  J 192-193 

16.  Map  of  Northampton,  Lehigh  and  Carbon  Counties,  Penn.,  Showing  Lo- 

cation of   Zinc    Mines   and   Smelteries 197 

17.  Map  of  Eastern  Tennessee,  Showing  Location  of  Zinc  Mines 199 

18.  Map  of  the  Zinc  Mining  District  of  Upper  Silesia 215 

19.  Transverse  Section  of  Spalling  and  Sorting  House 237 

20.  Transverse  Section  of  Ore  Sorting  House 238 

21-22.     Ore  Picking  Table 239 

23-24.     Robins  Conveying  and  Picking  Belt Facing  240 

25.  Diagram  of  Ore  Dressing  Process  at  the  Neue  Helene  Blende  Mill,  Upper 

Silesia    245 

26.  Diagram  of  the  Ore  Dressing  Process  Employed  in  the  Joplin  District,  Mo.  247 

27.  The  Ferraris  Magnetic  Separator 261 

28.  Arrangement  of  Magnetic  Separators  at  Friedrichssegen,  Germany 263 

29.  Plan  of  Magnetic  Separating  Works  at  Friedrichssegen 264 

30-31.     Calcining  Furnace  used  at  Friedrichssegen 265 

32-35.     The  Wenstrom  Magnetic  Separator 267 

36-37.     The  Wetherill  Magnetic  Separator,  Type  Xo.  1 270 

38.     Section  of  Pole  Pieces  of  Wetherill  Magnetic  Separator 271 

39-40.     The  Wetherill  Magnetic  Separator,  Type  No.  2 272 

41-42.     Modern  Form  of  Wetherill  Separator  with  Horizontal  Belt 274 

43.  General  View  of  Wetherill  Magnetic  Separator Facing  274 

44.  Modern  Form  of  Wetherill  Separator,  Three  Pole  Type 275 

45-48.     Wetherill  Magnetic  Separating  Plant  at  Lohmannsfeld,  Germany 279-283 

49-54.     Cleveland-Knowles    Magnetic    Separator 286-289 

55.  .Sample  Grinder    295 

56.  Riffle    Sampler    296 

f>7-59.     Jones'  Sampler   297 

60-61.     Elevations  of  Vezin  Automatic  Sampler  and  Elevator  Head 299 

62-66.     Arrangement  of  Vezin  Automatic  Samplers  in  Duplicate 300-301 

ix 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 

1. 

HISTORY  OF  THE  ZINC  INDUSTRY. 

Of  the  seven  common  metals  zinc  was  the  last  to  come  into  use  in  the 
arts,  and  its  production  on  a  commercial  scale  is,  indeed,  of  comparatively 
recent  date.  Nevertheless  there  is  evidence,  contrary  to  the  general  belief, 
that  it  was  known  by  the  ancients,  since  bracelets  made  of  it  have  been  found 
in  the  ruins  of  Cameros,  which  was  destroyed  500  B.  C.1  However,  this 
knowledge,  which  may  not  have  been  more  than  local,  seems  to  have  been 
lost  subsequently,  for  though  brass  was  in  use  at  that  time,  or  a  little  later, 
no  one  appears  to  have  been  aware  of  its  exact  character.2  Aristotle  in  the 
fourth  century  B.  C.  mentions  this  alloy  under  the  name  of  Mossincecian 
copper,  which  he  describes  as  having  been  produced  by  melting  copper  with 
a  peculiar  earth  found  on  the  shores  of  the  Blatxk  Sea.3  This  ore  was  called 
Kadpsia,  or  cadmia,  by  Dioscorides  and  Pliny,  the  latter  using  the  same 
word  to  designate  the  crusts,  consisting  of  impure  oxide  of  zinc,  which  col- 
lected in  the  brass  founders'  furnaces.4  The  alloy  made  with  this  material 
was  also  known  as  aurichalcum.  The  alchemists  of  the  middle  ages  were 
aware  of  the  effect  of  this  earth  upon  copper,  but  came  to  no  more  exact 
understanding  concerning  it  than  was  possessed  by  the  Romans. 

The  word  zinc  appears  to  have  been  first  used  by  Basil  Valentine,  occur- 
ring in  his  Currus  Triumphalis  Antimonii  and  also  in  his  Last  Testament, 
but  he  did  not  refer  to  it  especially  as  a  metal.  That  it  was  known  as  such 
was  first  mentioned  by  Paracelsus  (1493-1541),  who  said  in  his  treatise  on 
minerals:  "There  is  another  metal  called  the  zinken,  which  is  unknown  to 

1  Raoul   Jagnaux,  Traite1  de  Chlmie  Gen-  Tookey    of   an   undoubtedly    genuine    Greek 

6rale  (1887),  II,  385.  coin  of  Trajan  struck  in  Caria,  A.  D.  110: 

1  Moses  refers  to  brass  in  Numbers  xxxi,  Cu,    77-590%;    Zn,    20-700%;    Sn.    0-386%: 

22,  and  mention  is  made  of  it  elsewhere  in  Fe,  0-273%,  total,  98-949%. 

sacred  writings.     The  manufacture  of  brass  *  Beyond    doubt   metallic    zinc    was    often 

and  bronzes  seems  to  have  been  engaged  in  made  in  the  brass  furnaces  as  an  accidental 

by   the    Phrenicians   and   Assyrians   from    a  product.        The     4>evSoiev€o?     of     Strabo     is 

very  early  period.  thought      to     signify      drop-zinc,      probably 

*  Percy  quotes   the  following  analysis   by  formed  in   that   manner. 


2  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

the  fraternity,  and  is  a  metal  of  a  very  singular  kind.  It  can  be  melted,  for 
it  consists  of  three  fluid  principles,  but  it  is  not  malleable.  In  its  color  it  is 
unlike  all  others  and  does  not  grow  in  the  same  manner,  but  with  its  ultima 
materia  I  am  as  yet  unacquainted,  for  it  is  almost  as  strange  in  its  properties 
as  argentum  vinum.  It  admits  no  mixture,  will  not  bear  the  fabricationes  of 
other  metals,  but  keeps  itself  entirely  to  itself/'1  Consequently,  it  is  un- 
known to  whom  is  due  the  honor  of  its  isolation  as  a  metal,  but  it  is  probable 
that  the  discovery  was  first  made  in  the  East.  In  the  sixteenth  century  zinc 
was  brought  to  Europe  from  China  and  the  East  Indies  under  the  name  of 
tutanego  (whence  the  English  term  tutenegue),  and  it  is  likely  that  knowl- 
edge of  it  was  obtained  from  that  source  at  an  earlier  date.  Agricola  recog- 
nized in  1550  a  metal  accidentally  produced  in  the  furnaces  at  Goslar,  which 
he  called  zink,  or  conterf ey,  but  he  did  not  know  that  it  came  from  calamine. 

Libavius  (1595)  was  the  first  to  investigate  the  properties  of  zinc  with  any 
exactness,2  but  he  was  not  aware  that  it  could  be  derived  from  the  ore 
known  as  calamine,  which  was  then  used  extensively  in  brass  making.  The 
specimens  which  he  examined  came  through  Holland  from  the  East  Indies, 
and  he  spoke  of  it  as  a  peculiar  kind  of  tin  found  there  and  called  calaem. 
He  described  minutely  its  appearance  and  general  properties,  comparing 
them  with  those  of  other  metals,  and  noting  especially  that  when  it  was 
heated  in  the  air  it  took  fire  and  burned.  The  fact  that  Libavius  was  igno- 
rant of  the  connection  between  calamine  and  zinc  is  at  least  negative  evidence 
as  to  the  eastern  origin  of  the  latter.  However,  this  connection  was  soon 
established,  since  Glauber  (1603-1668)  mentioned  calamine  as  an  ore  of  zinc, 
though  the  exact  nature  of  the  metal  and  its  ores  continued  doubtful 
throughout  the  seventeenth  century.  As  late  as  1675  Lemery  believed  that 
zinc  was  identical  with  bismuth,  and  Boyle  often  employed  indiscriminately 
the  names  bismuth,  zinc  and  spiauter,  the  last  being  apparently  of  eastern 
origin  and  the  first  form  of  the  English  word  spelter. 

During  this  time  the  manufacture  of  brass  by  the  cementation  process  was 
actively  carried  on  at  numerous  places,  where  the  industry  is  so  ancient  that 
it  is  impossible  to  trace  its  beginning.  It  is  said  that  the  calamine  deposits 
of  Moresnet,  the  neutral  territory  between  Belgium  and  Germany,  were  ex- 
ploited at  intervals  from  the  beginning  of  the  middle  ages.3  In  1435  the 

1  According  to  some  authorities  zinc  was  2  Roscoe    and    Schorlemmer,    Treatise    on 

first  discovered  and  mentioned  by  Albertus  Chemistry   (New  York,  1889),  II,  i,  251. 

Magnus,    a   Dominican    monk   who    lived    in  3  According    to    M.     St.    Paul    de    Sinqay 

the  thirteenth   century.      He  called  it  mar-  (Engineering  and  Mining  Journal,  XXXV7!, 

ehasita    aurea.      The    sample    of    zinc    ex-  95)  there  are  ancient  documents  in  Belgium 

a  mined  by  Paracelsus  is  said  to  have  come  relating   that    the   calamine   near   Moresnet 

from  Carinthia,  a  duchy  of  Austria.  was  worked  at  the  beginning  of  the  seventh 


.  HISTORY    OF    THE    ZINC    INDUSTRY.  3 

concession  of  a  mine  by  the  Duke  of  Limbourg  is  mentioned,  and  in 
1439  there  is  reference  to  the  mountain  of  calamine  which  was  worked  by 
the  men  of  Aix.  This  mine,  which  was  then  abandoned,  had  been  worked 
in  former  years,  but  for  how  long  it  is  unknown.  However,  the  antiquity  of 
the  openings  was  such  that  the  place  had  received  the  name  of  the  Yieille 
Montagne  (Altenberg),  or  the  "Old  Mountain."  In  1454  a  grant  of  the 
mine  was  made  by  Philippe  le  Bon  to  Arnold  van  Zevel,  and  operations  were 
resumed.  The  ore  was  calcined  on  the  spot  with  charcoal  from  the  Herto- 
genwald,  and  was  then  sent  to  the  brass  makers  of  Aachen  (Aix-la-Chapelle), 
Stolberg,  and  Cornelius-Munster,  afterward  to  Dinant,  Bouvignes,  and 
Oignies,  in  the  neighborhood  of  Namur,  and  to  Liege  and  elsewhere  in  Bel- 
gium, the  rivers  Meuse  and  Sambre  being  utilized  for  its  transportation. 
The  process  of  brass  making  then  employed  consisted  in  imbedding  pieces 
of  copper  in  a  mixture  of  calamine  and  charcoal  in  crucibles,  which  were 
subjected  to  a  high  heat.  The  zinc  was  reduced  by  the  carbon,  and  vaporiz- 
ing combined  with  the  copper  to  form  brass.  The  process  was  slow  and 
wasteful,  and  it  was  impossible  to  produce  an  alloy  with  a  high  percentage 
of  zinc.  The  manufacture  of  brass  by  this  method  was  carried  on  at  Goslar, 
in  the  Lower  Harz,  in  the  sixteenth  century,  while  the  vast  deposits  of  ore 
in  the  vicinity  of  Beuthen,  in  Upper  Silesia,  were  worked  for  the  same  pur- 
pose at  an  equally  early  date.  In  England  brass  works  were  established  in 
Surrey  in  the  middle  of  the  seventeenth  century,1  and  in  1721  as  many  as 
30,000  persons  are  said  to  have  been  engaged  in  the  industry  there. 

In  1721  Henckel  published  his  discovery  that  zinc  could  be  obtained  from 
calamine,  and  he  is  named  by  Beckmann  as  the  first  who  intentionally  car- 
ried out  the  process.  However,  the  production  of  zinc  on  an  industrial  scale 
was  first  begun  in  England;  it  is  said  that  the  method  applied  was  Chinese, 
having  been  introduced  by  Doctor  Isaac  Lawson,  who  went  to  China  ex- 
pressly to  study  it.2  Be  that  as  it  may,  a  patent  for  a  process  of  distillation 
downward  was  granted  to  John  Champion  in  1739,  and  in  1740  he  erected 
works  at  Bristol  and  actually  began  the  manufacture  of  spelter,  but  the  pro- 
duction was  small,  and  the  more  part  of  that  used  continued  to  come 
from  India  and  China.3  In  1742  Van  Swab  produced  zinc,  at  Westerwick 

century,  but  they  are  of  doubtful  authen-  were  first  established  at  Bristol  about  1743. 
ticity,  and  the  best  evidence  is  that  it  was  "In  about  the  year  1766  Watson  visited  Mr. 
first  utilized  during  the  twelfth  century.  Champion's  works  near  Bristol  and  saw  the 
1A.  patent  for  the  use  of  calamine  in  brass  process  of  making  zinc,  which  at  that  time 
making  was  granted  during  the  reign  of  was  kept  rigidly  secret  Many  years  after- 
Queen  Elizabeth.  ward  he  published  an  accurate  description 

2  L.  Knab,  Traite  de  Metallurgie  des  Me-  of  the  process,  which  is  the  same  as  that 
taux  autres  que  le  fer  (1891),  p.  428.  hereafter  described  as  the  English  process" 

3  According  to  Bishop  Watson,  zinc  works  (Percy,  Metallurgy,  I,  521). 


4  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

in  Dalecarlia,  by  reducing  zinc  oxide  (obtained  from  blende)  with  coal, 
but  the  process  was  too  costly  and  was  therefore  abandoned.1  In  1746 
Margraaf  made  further  attempts,  and  finally  Cronstedt  and  Rinmann  per- 
fected the  process  of  distillation  per  ascensum.  None  of  these  early  experi- 
ments, however,  seems  to  have  been  of  much  importance;  certainly  none  of 
them  led  to  the  establishment  of  a  permanent  industry,  which  did  not 
begin  until  more  than  80  years  after  HenckeFs  discovery. 

The  principle  upon  which  the  modern  process  of  zinc  smelting  is  based,  or 
rather  the  method  of  carrying  out  that  principle  in  practice,  was  discovered 
in  Silesia  in  1799,  or  about  that  time.  Contemporaneously  a  practical 
method  of  zinc  smelting  was  devised  and  put  in  operation  in  Carinthia. 
A  similar  discovery  was  made  accidentally  and  independently  in  Belgium 
in  1805  by  the  Abbe  Dony,  who  does  not  appear  to  have  been  acquainted 
with  the  contemporary  work  of  others  in  the  same  direction.  The  two 
processes  of  zinc  smelting,  the  Silesian  and  Belgian,  in  use  at  the  present 
time  have  been  developed  from  those  beginnings.  Some  features  of  the 
former  have  been  introduced  in  the  latter,  and  vice  versa,  but  there  have 
been  no  revolutionary  improvements  in  either,  as  in  the  metallurgy  of 
copper  and  lead,  and  each  remains  essentially  unchanged.  Numerous  at- 
tempts have  been  made  by  zinc  metallurgists,  notably  by  Miiller,  Lencau- 
chez,  Clerc,  Thum,  Kohler,  and  Hempel,  to  reduce  the  cost  of  producing 
zinc  by  distilling  in  shaft  furnaces  instead  of  in  the  small  retorts  that  have 
been  used  for  100  years,  but  none  of  those  experiments  has  led  to  the 
desired  end,  because  it  has  been  impossible  to  prevent  oxidation  of  the  zinc 
and  the  formation  of  zinc  powder  in  comparatively  large  quantities,  thereby 
giving  products  which  must  be  reworked  in  small  retorts  and  lead  to  higher 
metallurgical  losses. 

BELGIUM. — Under  the  Dukes  of  Limbourg  and  of  Burgundy,  as  well  as 
under  the  Spanish  dominion,  the  Vieille  Montagne  mines  were  sometimes 
leased  to  private  parties — never  for  more  than  twelve  years,  however — and 
sometimes  were  worked  on  government  account,  the  last  system  being  fol- 
lowed particularly  under  the  Archduke  Albert  and  later  in  the  time  of 
Philippe  IV,  King  of  Spain.  After  the  annexation  of  the  Belgian  provinces 
to  France,  in  1795,  the  Eepublican  Government  worked  the  Vieille  Mon- 
tagne for  the  good  of  the  nation,  but  under  this  regime  the  success  of  the 
exploitation  fell  off,  and  the  Imperial  Government  renounced  it,  ceding  the 
mine  in  1806  to  the  Abbe  Daniel  Dony,  a  chemist  of  Liege,  "with  the  obli- 
gation of  making  experiments,  which  could  be  recognized  as  useful,  to  de- 

1  Phillips,  Elements  of  Metallurgy  (1891),  p.  551. 


HISTORY    OP    THE    ZINC    INDUSTRY.  0 

monstrate  his  ability  to  reduce,  by  the  aid  of  proper  furnaces,  calamine  to 
the  metallic  state." 

The  Societe  de  la  Vieille  Montagne,  in  a  pamphlet  entitled  L'Industrie 
du  Zinc,  presented  at  the  Exposition  Universelle  de  1889,  at  Paris,  from 
which  the  foregoing  details  concerning  the  history  of  the  zinc  deposits  of 
Moresnet  have  been  taken,  states  that  the  Emperor  thus  ordered  Dony,  in 
a  manner,  to  discover  a  method  of  winning  zinc,  and  Dony  obeyed  and  dis- 
covered it,  although  such  discoveries  are  rarely  made  by  decree.  The  prob- 
ability is,  however,  that  Dony,  who  had  been  experimenting  on  the  subject 
since  1780,  expressed  to  the  government  his  ability  to  produce  zinc,  and 
asked  for  the  concession  of  the  mines,  which  was  granted  on  the  condition 
tl  tat  he  should  prove  his  statements. 

Dony's  success  was  finally  achieved  accidentally,  after  a  long  series  of 
disappointing  results.  The  story  of  the  actual  discovery  is  classical.  When 
endeavoring  to  extract  zinc  from  calamine  by  fusion  in  a  reverberatory  fur- 
nace it  occurred  to  him  that  the  heat  applied  was  not  sufficiently  high,  and 
he  added  coal  dust  to  the  mineral  to  attain  a  greater  temperature.  In  order 
to  observe  what  took  place  in  the  interior  of  his  furnace,  he  built  an  ordi- 
nary flower-pot  into  one  side  to  serve  as  a  peep-hole  through  which  he  could 
look.  The  furnace  having  been  charged  and  the  firing  begun,  drops  of 
zinc  were  observed  to  condense  on  the  inside  of  the  flower-pot,  which  was 
cooler  than  the  furnace  itself,  and  the  method  of  extracting  the  metal  by 
distillation  was  thus  discovered. 

Dony's  experiments  were  carried  out  in  a  little  workshop  in  the  Faubourg 
St.  Leonard  at  Liege,  where  he  subsequently  built  furnaces  and  commenced 
the  production  of  zinc  on  a  commercial  scale.  There  was  no  use  then,  how- 
ever, for  the  new  metal,  with  which  the  public  was  unfamiliar,  and  it  was 
necessary  to  raise  it  to  the  rank  of  the  needful  commodities.  This  task  was 
beyond  the  power  of  one  man  alone,  and  Dony,  having  ruined  himself,  died 
without  having  accomplished  it. 

Dominique  Mosselman,  a  man  of  vast  energy,  took  up  Dony's  work  in 
1818,  devoting  his  life  to  perfecting  the  process  for  making  zinc  and  to 
establishing  a  market  for  it,  but  nevertheless  at  his  death,  in  1837,  the  in- 
dustry could  scarcely  be  said  to  exist  in  the  west  of  Europe  except  in  expec- 
tation.1 In  order  to  settle  his  estate,  Mosselman's  children  founded  the  So- 
ciete de  la  Vieille  Montagne,  with  a  capital  of  7,000,000  fr.,  divided  into  7,000 
shares  of  1,000  fr.  each,  and  since  that  time  (1837)  said  company  has  been 
the  leading  zinc  producer  of  Europe. 

1  These  facts  are  matters  of  record,  but  development  which  the  zinc  industry  in 
the  situation  seems  strange  in  view  of  the  Silesia  had  already  attained  at  that  time. 


C  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

The  property  of  the  Vieille  Montagne  Company,  at  the  time  of  its  organ- 
ization, consisted  of  the  calamine  mine  in  Moresnet,  the  St.  Leonard  zinc 
works  at  Liege,  two  small  rolling  mills  at  Horn  and  Houx,  in  France,  and 
a  new  smelting  works  at  Angleur,  on  the  river  Ourthe,  a  branch  of  the 
Meuse,  which  was  then  in  course  of  construction.  A  few  months  later  the 
company  bought  the  rolling  mills  at  Bray,  in  France,  and  at  Tilff,  in  Bel- 
gium. For  nearly  10  years  the  company  had  a  hard  struggle,  but  after 
1846,  in  which  year  the  direction  of  its  business  was  intrusted  to  M.  St. 
Paul  de  Singay,  who  continued  to  manage  it  until  1890,1  there  was  a  rapid 
advance  in  its  affairs.  The  Societe  Anonyme  des  Mines  et  Fonderies  de 
Zinc  et  de  Plomb  de  la  Nouvelle  Montagne  established  works  at  Engis,  in 
1845,  and  other  companies  engaged  in  the  industry  at  about  the  same  time.- 
CARINTHIA. — Zinc  smelting  was  begun  at  an  early  date  in  this  duchy 
of  Austria,  and  by  a  method  of  distinct  character,  the  inception  of  the 
process  and  its  application  being  due  to  Bergrath  Dillinger,  of  Klagenfurt. 
His  first  furnace  was  built  in  1799  at  Dollach,  near  Gross  Kirchheim,  in 
the  Mollthale;  according  to  some  authorities  this  was  the  earliest  furnace 
for  the  distillation  of  zinc  in  use  on  the  Continent  of  Europe.3  In  1800 
Dillinger  was  appointed  "director  of  all  the  zinc  works  of  Austria,"  and  in 
1801  he  erected  a  second  plant,  at  Delach  in  the  Drauthale.  Dillinger's 
furnace,  which  was  wood-fired,  comprised  135  vertical  retorts,  4-5  in.  in 
diameter  at  the  bottom  and  3-5  in.  at  the  top  (inside  measurements)  and 
40  in.  long.  Only  84  of  the  retorts  were  charged  with  ore,  each  one  re- 
ceiving from  5  to  6  Ib. 

Metallurgical  literature  contains  but  few  references  to  these  early  Carin- 
thian  zinc  works  and  their  history  is  uncertain.  The  plant  at  Delach  was 
described  by  Hollunder,  in  his  Tagebucli  einer  metallurgischen  Eeise,  pub- 
lished at  Niirnberg  in  1824;  a  full  abstract  of  his  description  is  to  be 
found  in  Percy's  Metallurgy,  The  distillation  in  the  small  vertical  retorts 
was  very  expensive  and  the  loss  of  metal  was  high.  Operations  at  Dollach 
and  Delach  appear  to  have  been  discontinued  in  the  early  part  of  the  nine- 
teenth century.  The  employment  of  a  modified  form  of  the  Carinthian 
furnace  was  proposed  about  1880  by  various  metallurgists,  among  others 
by  Binon  and  Grandfils  and  by  Chenhall,  but  their  projects  did  not  advance 
beyond  the  experimental  stage,  and  subsequent  improvements  in  the  execu- 
te was  then  succeeded  by  his  son,  M.  some  of  the  other  zinc  smelteries  of  Bel- 
Gaston  St.  Paul  de  Singay,  who  is  the  pres-  gium  are  as  follows :  Ougre>,  1850 ;  Pra- 
ent  administrator-general  of  the  company.  yon,  1853 ;  Corphalie,  1842 ;  Ampsin,  1841  • 

'The  Valentin-Cocq  and  Flone   works   of       Antheit,   1842;   Seilles,  1857;   Boom,   1890; 
the    Societe    Anonyme    de    la    Vieille    Mon-       Overpelt.  1893. 

tagne  were  built  in  1851  and  1855  respec-  3  V.    Spirek,    Oest.    Zts.     (1881),    XXIX, 

tlvely.     The  dates  of  the  establishment   of       323. 


HISTORY     OF     THE     ZINC     INDUSTRY.  7 

tion  of  the  Belgian  process  enabled  the  distillation  of  ores  high  in  lead, 
which  was  the  chief  advantage  the  use  of  vertical  retorts  was  conceived  to 
present. 

GREAT  BRITAIN. — The  first  zinc  smelting  works  in  England  were  built 
in  17401  by  John  Champion,  to  whom  reference  has  previously  been  made. 
He  employed  the  large  pots,  characteristic  of  the  so-called  English  process 
(which  survived  until  about  1860),  wherein  the  vapor  is  conducted  down- 
ward through  a  pipe  extending  from  the  bottom  of  the  pot.  The  first 
works  at  Swansea,  which  is  now  the  chief  center  of  the  British  zinc  indus- 
try, was  established  by  the  Vivians  in  1835. 2  The  early  English  furnaces 
fell  gradually  into  disuse,  being  replaced  by  furnaces  of  the  Silesian  type, 
which  have  in  late  years  been  to  a  large  extent  displaced  in  turn  by  Belgian 
furnaces. 

SILESIA. — The  history  of  the  Silesian  zinc  industry  is  similar  to  that  ol 
the  Belgian.  It  began  a  few  years  earlier,  however,  and  once  having  been 
started  grew  more  rapidly  and  more  regularly,  so  that  it  seems  strange  that 
the  Belgians  did  not  borrow  more  from  the  experience  of  the  Silesian  metal- 
lurgists. The  existence  of  the  great  deposits  of  calamine  in  the  neighbor- 
hood of  Beuthen,  in  Upper  Silesia,  was  known  in  the  sixteenth  century,  and 
even  at  that  time  the  ore  was  used  for  the  manufacture  of  brass  by  cementa- 
tion. The  zinc  mining  industry  began  to  assume  important  proportions 
in  this  Province  in  the  eighteenth  century,  when  Georg  von  Giesche,  a 
merchant  of  Breslau,  received  from  the  Emperor  Leopold  (Nov.  22,  1704) 
the  privilege  of  exploiting  the  zinc  deposits  of  the  Beuthen  domain  and  the 
right  of  selling  the  ore  outside  of  Silesia,  which  grant  was  prolonged  until 
1802  by  agreement  with  the  Counts  Henckel,  the  great  landlords  of  the 
district.  Toward  the  end  of  the  century  the  industry  increased  largely  in 
importance,  the  production  averaging  10,000  centners  of  calcined  calamine 
per  year  between  1780  and  1792  and  rising  to  18,000  centners  in  1792.3 
The  cost  of  production  was  very  small,  and  the  selling  price  of  the  mineral 
was  about  four  marks  per  centner.  The  calamine  was  at  first  calcined  in 
open  heaps,  but  subsequently  calcining  furnaces,  designed  after  the  form  of 
baking  ovens  and  fired  with  stone-coal,  were  introduced. 

The  zinc  industry  of  Upper  Silesia  was  revolutionized  at  the  beginning 
of  the  nineteenth  century,  when  the  manufacture  of  spelter  was  begun. 
This  was  due  to  the  Kammerassessor  Johann  Ruhberg  of  Pless,  who  learned 
the  art  in  England  (where  zinc  smelting  was  then  being  carried  on  by  the 

1  The  authorities  differ  as  to  the  date.  of  the  economic  and  technical  conditions  of 

2  George   Borgnet,    Revue    Universelle   des  the  Welsh  zinc  industry  at  that  time. 
Mines,    Vol.    II,    November    and    December,  3  The  centners  referred  to  in  this  section 
1877.     This   paper  contains   complete  data  are  the  German  centners  of  100  Ib.  =50  kg. 


PRODUCTION    AXD    PROPERTIES    OF    ZINC. 

English  process  of  distillation  downward)  and  brought  the  secret  to  Upper 
Silesia.  It  is  incomprehensible  indeed  that  10  years  later  there  should 
have  been  no  knowledge  in  Belgium  of  what  was  being  done  in  this  branch 
of  metallurgy  in  England,  the  two  countries  being  separated  by  only  a 
narrow  strip  of  water,  while  the  news  had  previously  penetrated  eastward  to 
the  Polish  frontier.  Ruhberg  constructed  the  first  zinc  furnace  in  Upper 
Silesia,  in  the  neighborhood  of  Wessola,  utilizing  for  this  purpose  the  pots 
in  a  wood-fired  glass-furnace,  and  it  is  noteworthy  that  the  Silesian  zinc 
furnace,  in  contradistinction  to  the  Belgian,  preserves  to  this  day  traces  of 
the  glass-furnaces  from  which  it  originated.1 

After  Ruhberg's  first  experiments  others  were  taken  up  at  the  Koenig- 
lichen  Friedrichs-Bleihiitte  and  later  at  the  Koenigs-Eisenhiitte.  In 
those  experiments  the  round  form  of  the  Wessola  glass-furnace 
was  still  preserved,  but  more  practical  retorts  for  reduction  of 
the  ore  were  adopted,  long  half  cylinders  being  substituted  for 
the  original  glass-pots.  The  experiments  with  the  improved  retorts  gave 
such  favorable  results  that  the  erection  of  larger  zinc  works  at  Koenigshiitte 
was  soon  undertaken.  These  works,  the  Lydogniahiitte,  came  into  opera- 
tion in  1809,  and  on  December  16  of  the  same  year  the  Bergwerksgesell- 
schaft  Georg  von  Giesche's  Erben  put  in  operation  a  zinc  furnace  with  four 
muffles  at  its  calcining  works  at  Scharley,  the  success  of  which  led  to  the 
establishment  of  the  Siegismundhiitte,  with  10  furnaces,  at  the  same  place 
in  the  following  year.  In  1813  the  Konkordiahiitte,  also  situated  at  Schar- 
ley, was  built  by  the  same  company.  The  production  of  the  two  works  of 
Giesche's  Erben  from  1811  to  1814,  in  spite  of  the  war  which  was  then 
raging  throughout  Europe,  amounted  to  6,279  centners  of  spelter.  Several 
other  small  zinc  works  had  also  been  established  in  Upper  Silesia  in  the 
meanwhile,  and  the  increasing  production  caused  a  heavy  fall  in  the  price 
of  the  metal.  The  consumption  of  coal  in  1815  was  from  four  to  five  tons 
per  ton  of  calamine,  and  the  success  of  the  zinc  works  situated  near  the 
zinc  mines  and  remote  from  the  coal,  or  otherwise  unfavorably  located,  was 
checked  by  the  cost  and  difficulty  of  procuring  fuel.  This  led  to  the  estab- 
lishment of  new  zinc  works  near  the  collieries,  the  Giesche's  Erben  first 
building  the  Georgshiitte,  near  the  Fanny  coal  mine  at  Michalkowitz,  in 
1818.  These  works  had  eight  furnaces  of  eight  muffles  each,  and  produced 
2,638  centners  of  zinc  in  1818  at  a  cost  of  13-5  marks  per  centner.  The 

1  The  precise  date  of  Ruhberg's  first  fur-  zinc  smeltery   on   the   Continent  belongs   to 

nace    at    Wessola    is    uncertain ;    some    au-  Ruhberg   or   to   Dillinger.      The   probability 

thorities     say     1798;     others     1799;     and  appears  to  be,  however,  that  Dillinger  was 

others     1800.       It     is     doubtful     therefore  the  earlier, 
whether  the  credit  of  establishing  the  first 


I^ISTORY     OF     THE     ZINC     INDUSTRY.  9 

two  works  at  Scharley  were  then  closed  down.  In  1822  the  Georgshiitte 
was  increased  by  the  erection  of  eight  new  furnaces,  each  with  10  muffles, 
while  two  muffles  per  furnace  were  added  to  those  previously  in  use.  The 
production  of  these  works  then  rose  to  8,571  centners  and  the  cost  of  pro- 
duction was  reduced  to  eight  marks  per  centner.1 

The  number  of  zinc  works  in  Upper  Silesia  increased  very  rapidly  after 
1815;  besides  the  Georgshiitte,  the  Hugo  and  Liebehoffnung  works  were 
built  at  Neudorf  in  1818  and  1820  respectively,  while  the  Clarahiitte  was 
put  in  operation  in  1822  and  the  construction  of  the  Davidhiitte  at  Chropac- 
zow,  with  five  double  furnaces  of  20  muffles  each,  was  begun  in  1825.  The 
Davidhiitte  was  the  forerunner  of  the  present  great  works  at  Lipine.  The 
total  production  of  spelter  in  Upper  Silesia  in  1825  amounted  to  more  than 
200,000  centners  and  largely  exceeded  the  consumption  at  that  time.  Con- 
sequently the  price  of  zinc  fell  to  9@12  marks  per  centner,  and  many  of 
the  zinc  works,  whose  supply  of  ore  was  not  assured,  were  closed  down.2 

The  normal  Silesian  furnace  as  installed  at  the  Lydogniahiitte,  Georgs- 
hiitte,  Davidhiitte  and  Liebehoffnungshiitte  previous  to  1820  retained  the 
dome-shape  arch  of  the  glass-furnaces  and  had  a  plane-grate  upward  of 
6  ft.  in  length,  extending  in  its  longer  direction,  which  divided  it  into  two 
equal  parts.  On  each  side  of  the  grate  there  were  arranged  five  muffles, 
about  4  ft.  in  length  and  12  to  15  in.  in  width  and  height,  inside  measure- 
ments. The  walls  of  the  muffles  were  much  thicker  than  nowadays,  and 
because  of  that  and  the  great  width  of  the  muffles  a  fair  extraction  of  zinc 
was  attained  only  by  means  of  an  immoderate  consumption  of  fuel.  The  first 
important  improvement  was  made  in  the  '20's,  at  the  Georgshiitte,  by  the 
Hiittenmeister  Knaut,  who  reduced  the  width  of  the  muffles  more  than 
half  and  set  two  in  each  opening  in  the  sides  of  the  furnace.  This  inno- 
vation was  found  so  advantageous  that  it  was  quickly  adopted  by  all  of  the 
other  smelters.  At  each  corner  of  the  furnace  there  was  a  low  chimney, 
through  which  the  gases  of  combustion  were  directly  discharged.  In  the 
Wilhelminehlitte,  built  in  1834,  furnaces  with  20  muffles  were  installed 
and  the  number  of  muffles  was  gradually  increased,  but  the  type  of  furnace 
remained  essentially  the  same  until  the  '60s,  when  the  furnaces  designed  by 

1  In  1874  the  cost  of  smelting  (not  includ-  spelter  was  10-19  and  10-45  marks  respect- 
ing general  expense)  at  the  Pauls-  and  Wil-  ively,  making  the  total  cost  of  production 
helminehiitten  was  7-91  marks  per  centner  18-10  and  16-42  marks. 

of  50  kg.   in  the  case  of  24-muffle   "unter-  2  These  data  concerning  the  development 

windofen"  and  5-97  marks  in  the  case  of  56-  of  the   zinc  industry  in  Upper   Silesia  are 

muffle  Siemens  regenerative  furnaces    (Max  drawn   mostly  from   the  excellent  book   by 

Georgi,    Berg-u.    Hiittenm.    Ztg.,    March    9.  Doctor  H.  Voltz,  Die  Bergwerks-  und  Htit- 

1877,  et  seq.).     These  results  were  obtained  tenverwaltungen    des    Oberschleslschen    In- 

with    ore   yielding    11-17%    and    11-39%   Zn  dustrie-Bezirks. 
respectively.     The  ore  cost   per  centner  of 


10  PRODUCTION    AND   PROPERTIES    OF   ZINC. 

Thometzek  and  others,  having  a  central  chimney  and  down  draught  method 
of  heating  (imitating  the  type  of  furnace  installed  at  Valentin-Cocq,  Bel- 
gium) came  into  use.  The  form  of  the  grate  was  modified  so  as  to  permit 
of  the  satisfactory  combustion  of  the  small  sizes  of  coal,  and  the  method 
of  firing  with  an  undergrate  blast  (Unterwindofen)  was  introduced.  The 
first  Siemens  furnace  was  erected  at  the  Wilhelminehutte  in  1869.  The  old 
Silesian  furnaces  were  provided  with  the  knee-form,  or  drop-zinc  con- 
densers; these  remained  in  use  at  the  Bobrekhiitte  as  late  as  1877.  The 
metallurgical  progress  in  Upper  Silesia  previous  to  1860-1870  was  appar- 
ently very  slow  indeed. 

Of  the  great  zinc  producers  of  Silesia  at  the  present  time  the  Giesche's 
Erben  engaged  in  the  industry  in  1809,  as  above  described;  the  Counts 
Henckel  von  Donnersmarck  in  1818;  the  Schlesische  Actiengesellschaft  fur 
Bergbau  und  Zinkhiittenbetrieb  in  1853,  taking  over  works  previously  in 
operation,  of  which  the  Davidhiitte,  built  in  1825,  was  the  first  establish- 
ment ;  while  the  great  works  of  the  Herzog  von  Ujest,  the  Hohenlohehiitte, 
were  not  built  until  1871. 

The  technical  development  of  the  zinc  industry  in  Upper  Silesia  is  out- 
lined in  the  history  of  the  Wilhelmine  works  of  the  Bergwerksgesellschaft 
Georg  von  Giesche's  Erben.  Those  works  were  built  at  Schoppinitz  in 
1834.  According  to  the  old  records  of  the  company  the  calamine  which 
was  smelted  in  the  early  years  of  their  operation  assayed  from  40  to  45  % 
Zn  and  yielded  about  30%  of  metal ;  i.e.,  out  of  400  to  450  kg.  of  zinc  in  the 
ore  about  300  kg.  were  got  as  spelter,  which  is  approximately  as  good  metal- 
lurgical work  as  is  done  with  modern  furnaces,  fitted  with  much  better 
retorts  than  were  formerly  obtainable  and  heated  to  a  much  higher  temper- 
ature. 

The  explanation  of  this  apparently  good  work  is  that  in  former  times 
the  miners  were  accustomed  to  give  legitimately  an  overweight  of  10% 
and  the  smelters  not  infrequently  obtained  illegitimately  an  overweight  of 
as  much  as  20%.  If  allowance  be  made  for  such  errors  in  the  data  it  would 
appear  that  the  old  Silesian  smelters  used  to  experience  a  loss  of  33%  of 
the  zinc  contents  of  the  ore  which  they  smelted.  Considering  the  con- 
ditions under  which  they  worked  even  such  a  loss  was  not  an  excessive  one 
and  the  fair  extraction  of  metal  was  due  no  doubt  to  the  high  grade  and 
docile  character  of  the  ore  which  was  available  to  them.  The  calamines  of 
that  day  probably  gave  an  actual  yield  of  about  27%  Zn.  The  calamine 
which  is  smelted  now  assays  about  13%  Zn  and  gives  a  yield  of  about  10 %.1 

1  This  refers  to  calamine  alone.     The  grade   of  the   ore   commonly   smelted   nowadays   is 
raised  by  admixture  of  roasted  blende. 


HISTORY     OF     THE     ZINC     INDUSTRY.  11 

The  value  of  the  calamine  produced  in  Upper  Silesia  was  always  more  or 
less  dependent  upon  the  price  of  spelter,  but  formerly  it  was  not  made  to 
correspond  therewith  so  closely  as  now,  and  the  difference  between  the  value 
of  zinc  in  the  ore  and  zinc  in  pigs  was  generally  greater.  The  ore  which  is 
smelted  at  present  was  formerly  cast  aside  as  worthless,  because  of  its  low 
grade. 

In  the  period  about  1835  the  consumption  of  coal  in  smelting  amounted 
to  250-270  kg.  per  100  kg.  of  ore,  according  to  the  records  of  that  date, 
but  taking  into  consideration  the  20%  overweight  in  ore  referred  to  above, 
the  actual  consumption  of  coal  was  probably  about  2-2  times  the  weight  of 
the  ore.  This  ratio  of  coal  consumption  was  not  reduced  to  speak  of  until 
the  introduction  of  the  Siemens  furnace.  The  coal  employed  in  1835  con- 
sisted of  about  80 %  lump  coal  and  20%  slack;  the  latter  was  sifted  before 
use  and  the  dust  thrown  away.  The  lump  coal  cost  17-5  pfennigs  per 
centner ;  the  slack  cost  six  pfennigs.  Notwithstanding  the  low  cost  of  each 
of  those  kinds  per  se  at  that  time,  the  average  cost  was  higher  than  that  of 
the  coal  used  at  the  present  time.  On  the  other  hand  the  cost  of  the  cinder 
employed  as  reduction  material  is  now  higher  than  formerly.  It  was  esti- 
mated in  1883  that  the  average  cost  of  heating  and  reduction  coal  was  five 
pfennigs  per  centner  higher  than  in  1835.  In  1835,  in  smelting  100  cent- 
ners of  calamine  about  225  centners  of  coal  costing  41  marks  were  used ;  in 
1883  only  130  centners  of  coal  and  cinder,  costing  23  marks.  An  equally 
striking  economy  in  the  consumption  of  coal  per  centner  of  zinc  produced 
has  not  been  attained,  on  account  of  the  increased  poverty  of  the  ore,  as  a 
result  of  which  eight  centners  of  coal  and  cinder,  costing  1-6  marks,  were 
required  per  centner  of  zinc  in  1883,  whereas  in  1835  the  consumption  of 
coal  per  centner  of  zinc  was  only  seven  centners,  costing  1-3  marks. 

The  cost  of  labor  in  smelting  in  Upper  Silesia  has  also  increased.  In 
1850  wages  amounted  to  19  marks  per  100  centners  of  calamine;  in  1883 
they  had  risen  to  26  marks,  and  that  in  spite  of  the  introduction  of  labor- 
saving  improvements.  A  smelter  who  was  formerly  paid  one  mark  per 
shift  got  from  3-2  to  3-5  marks  in  1883 ;  stokers  who  received  formerly  75 
pfennigs  were  paid  50  years  later  from  2-25  to  2-5  marks ;  while  the  wages 
of  helpers  increased  from  50  pfennigs  to  1  or  1-5  marks.  In  1835  the  cost 
of  labor  per  centner  of  zinc  was  but  little  over  0-60  mark ;  in  1883  it  was 
nearly  three  times  as  much.  The  cost  of  refractory  material  increased  as 
well ;  and  also  the  cost  of  furnace  repairs,  partly  because  of.  the  greater  cost 
of  refractory  material  and  partly  because  of  the  greater  complexity  of  the 
improved  furnaces.  On  the  other  hand  the  lower  cost  of  ironwork  was 
to  some  extent  an  offset  in  that  item.  Taking  into  consideration  the  cost  of 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 

material  and  labor  and  the  consumption  thereof,  the  expense  of  smelting 
100  centners  of  calamine  was  about  11%  higher  in  1883  than  in  1835,  while 
the  cost  per  centner  of  zinc  was  nearly  double.  The  conditions  which 
existed  in  Upper  Silesia  in  1883  were  substantially  the  same  as  at  the 
present  time,  but  if  anything,  the  cost  of  coal  is  now  dearer  than  it  was 
then,  and  labor  also  is  somewhat  higher. 

The  price  of  zinc  since  the  metal  first  became  of  industrial  importance 
has  been  subject  to  curious  fluctuations.  Unlike  most  of  the  other  metals 
of  which  the  value  has  gradually  decreased  with  improved  methods  of  win- 
ning, that  of  zinc  is  now  but  little  below  the  rate  of  previous  years,  and  is 
actually  higher  than  the  general  market  price  during  the  first  two  decades 
of  the  commercial  history  of  the  metal.  This  remarkable  circumstance  is 
due  to  the  slight  demand  at  first  for  the  new  and  but  little  known  metal,  and 
the  fact  that  the  cost  of  production  in  Silesia  80  years  ago  was  less  than 
at  present,  the  increase  in  the  wages  of  labor  and  the  cost  of  ore  and  coal 
since  1814  having  more  than  kept  pace  with  the  saying  effected  by  new  and 
improved  mining  and  metallurgical  methods.  Previous  to  1814  the  price  of 
zinc  in  Upper  Silesia  appears  to  have  been  generally  over  30  marks1  per  50  kg. 
($150  per  ton),  but  upon  the  rapid  development  of  the  industry  in  that 
year  there  was  a  falling  off,  so  that  in  1814  the  price  was  21  marks  per 
centner  ($105  per  ton),  20  marks  ($100)  in  1815,  and  in  1817  and  1818 
only  16  marks  ($80).  In  1820  the  price  fell  further  to  10-5  marks 
($52*50),  which  was  lower  than  the  average  cost  of  production  at  that  time, 
wherefore  arose  the  first  crisis  in  the  zinc  industry,  many  of  the  newly 
established  works  being  obliged  to  close. 

*  Until  1820  the  chief  market  for  Silesian  zinc  was  in  Asia,  whither  it  was 
shipped  through  Russia ;  in  1821  exportations  to  British  India  were  begun, 
and  soon  grew  to  such  an  extent  that  the  Chinese  zinc  was  driven  out  of 
that  market.  This  circumstance,  together  with  the  restricted  production 
and  the  erection  of  the  first  rolling  mills  at  Malapane,  Friedrichshiitte,  and 
Rybnik,  thus  affording  a  new  home  market  for  spelter,  sent  the  price  for  the 
metal  up  to  32  marks  ($160)  at  the  beginning  of  1823 ;  but  this  led  to  such 
a  great  increase  in  the  make  that  the  demand  was  quickly  outstripped,  and 
a  second  crisis  in  the  industry  resulted,  which  lasted  from  1826  to  1830. 
At  times  it  was  impossible  to  sell  zinc  at  all,  and  only  the  most  favorably 
situated  works  could  keep  in  operation,  the  production  of  the  Province  f  all- 

1  Zinc  is  quoted  in  Breslau  customarily  in  dollars  per  metric  ton  in  parentheses. 

German  centners    (50  kg.),  and  in  recount-  In    3809,    when    the    Lydogniahiitte    was 

ing  the  course  of  Silesian   zinc  that  form  built,  the  value  of  zinc  was  60  marks  per 

will  be  used,   with  the  equivalent  price  in  centner. 


I-nSTOliY     OF     THE     ZINC     INDUSTRY.  13 

ing  off  more  than  one  half  its  former  maximum.  The  lowest  point  was 
reached  in  1829,  when  spelter  was  quoted  at  nine  marks  ($45)  at  Breslau. 

In  1830  the  Silesian  zinc  industry  began  to  develop  on  a  sounder  basis. 
The  price  for  the  metal  remained  low  during  the  next  10  years,  but  sales 
became  more  regular  and  gradually  the  demand  began  again  to  exceed  the 
production,  in  consequence  of  which  prices  ruled  high  from  1840  to  1848, 
varying  from  1G  to  26  marks  ($80@$130).  The  political  disturbances  of 
1848-1850  then  gave  the  industry  a  setback,  which  lasted  until  1852,  prices 
ranging  from  11  to  13-50  marks  ($54@$67-50),  but  from  that  time  until 
1878  there  was  a  steady  period  of  prosperity,  which  was  only  interrupted  by 
the  financial  crises  of  1858  and  1873,  and  the  wars  of  1866  and  1870-1871. 
The  exhaustion  of  some  of  the  important  deposits  of  calamine  (especially 
the  Scharley  and  Marie  mines)  in  1870  led  to  a  decrease  in  production,  and 
an  increase  in  price  owing  to  the  higher  cost  of  ore ;  but  by  the  end  of  the 
decade  all  the  works  were  equipped  with  roasting  plants  for  the  treatment  of 
the  blende,  which  had  first  begun  to  be  exploited  in  1870.  The  supply  of 
the  sulphide  ore  being  large,  the  value  of  zinc  in  the  five  years  following 
1878  averaged  five  marks,  or  25%,  below  that  of  the  10  years  preceding 
1878,  and  in  1883  was  lower  than  it  had  been  for  30  years.  The  aver- 
age price  of  Silesian  zinc  per  centner  and  per  ton  at  Breslau  by  decades 
since  1830  was  as  follows:  1830-1840,  13-04  marks  ($65-20) ;  1840-1850, 
18-17  marks'  ($90-85)  ;  1850-1860,  18-42  marks  ($92-10)  ;  1860-1870, 
18-32  marks  ($91-60);  1870-1880,  20-15  marks  ($100-75).1  The  history 
of  spelter  since  1880  is  summarized  in  Chapter  IV. 

UNITED  STATES. — Zinc  was  first  made  in  the  United  States  about  1838, 
at  the  Government  Arsenal  in  Washington,  from  the  red  zinc  ore  of  New 
Jersey,  for  the  brass  designs  of  the  standard  weights  and  measures  ordered 
by  Congress.  The  process  was  so  expensive,  however,  as  to  preclude  any 
idea  of  producing  zinc  commercially  in  the  same  manner.  The  regular 
manufacture  of  zinc  was  first  undertaken  in  1850  at  Newark,  N.  J.,  by 
Richard  Jones,  the  ore  being  charged  into  Belgian  retorts  just  as  it  came 
from  the  mine.  The  experiment  proved  a  failure  owing  to  excessive  break- 
age of  the  retorts  due  to  the  high  tenor  of  the  ore  in  iron  and  manganese. 
Attention  was  then  directed  to  recovery  of  the  zinc  as  oxide,  and  a  furnace 
constructed  of  fire  brick  with  a  large  clay  muffle  was  designed,  which  with- 
stood the  corrosion  better  than  the  Belgian  retorts.  A  row  of  these  was 
erected  in  connection  with  a  muslin  bag  apparatus  (invented  hv  Samuel  T. 

1  These  data  concerning  the  fluctuations  Gesellschaft  Georg  von  Giesche's  Erben,  en- 
in  the  price  of  Silesian  zinc  are  taken  from  Htled  Denkschrift  zur  Feier  des  fiinfzig- 
a  pamphlet  published  by  the  Bergwerks  j-ihrigen  Bestehens  der  Wilhelminezinkhlitte. 


14  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

Jones)  to  collect  the  fume,  and  the  regular  manufacture  of  zinc  oxide  was 
begun.  In  1851  Samuel  Wetherill,  one  of  the  officers  of  the  New  Jersey 
Zinc  Co.,  invented  the  process,  since  known  as  the  Wetherill  process,  by 
which  the  extraneously  heated  muffle  was  done  away  with.  The  ore  mixed 
with  anthracite  coal  was  thrown  in  a  layer  3  to  -i  in.  thick  upon  a  hearth 
composed  of  perforated  cast-iron  plates,  1  in.  thick;  the  door  was  closed 
and  cold  air  blown  under  the  grate,  which  passing  through  the  charge 
raised  the  temperature  to  such  a  point  that  the  ore  in  contact  with  the 
carbon  was  reduced  to  metallic  zinc,  vaporized  and  oxidized,  passing  off  as 
a  white  smoke  to  the  collecting  apparatus,  where  the  products  of  combus- 
tion strained  through  the  muslin,  leaving  the  oxide  inside  the  bags.  This 
process  proved  so  successful  that  it  was  introduced  immediately  and  has 
remained  in  use  without  essential  change  up  to  the  present  time.  A  de- 
scription of  the  first  works  and  mines  was  given  in  Whitney's  Metallic 
Wealth  of  the  United  States,  published  in  1854. 

Attempts  to  produce  spelter  were  not  given  up,  however,  and  in  1856 
experiments  with  a  Silesian  furnace  were  made  at  Bethlehem,  Penn.,  by  the 
Lehigh  Zinc  Co.  They  proved  unsuccessful,  neither  the  anthracite  fuel  nor 
the  retort  clay  being  apparently  adapted  to  the  purpose.  In  1857  Messrs. 
Matthiessen  and  Hegeler,  who  had  just  come  to  the  United  States  from  the 
school  of  mines  at  Freiberg,  Saxon}^  obtained  permission  from  the  com- 
pany to  experiment  on  their  own  account  at  the  abandoned  plant.  They 
did  it  on  a  small  scale,  using  one  muffle  placed  in  a  kiln  altered  for  the  pur- 
pose. They  demonstrated  that  anthracite,  as  well  as  New  Jersey  clay,  could 
be  used,  and  made  some  spelter  in  this  experimental  way,  but  failed  to  come 
to  an  agreement  with  the  owners  of  the  property  for  building  works,  largely 
on  account  of  the  financial  crisis  prevailing  at  that  time.  They  then  turned 
their  attention  to  the  West,  where  they  studied  the  zinc  deposits  of  Wiscon- 
sin, and  late  in  1858  began  the  erection  of  the  present  works  at  Lasalle. 
Lasalle  was  selected  as  the  point  where  the  Illinois  coal  field  approached 
nearest  to  the  Wisconsin  zinc  mines.  The  Joplin  mines  were  unknown  at 
that  time.1 

In  the  meanwhile  experiments  were  still  carried  on  in  New  Jersey  and 
Pennsylvania  by  Samuel  Wetherill,  Joseph  Wharton  and  others,  who  in- 
vented furnaces  of  various  types,  but  the  several  undertakings  failed,  and 
after  all  the  Lehigh  Zinc  Co.  returned  to  the  Belgian  furnace  and  in  1860 
erected  works  at  Bethlehem,  Penn.  After  that  date  works  were  built  at 
Newark,  Jersey  City,  and  Bergen  Point,  N.  J.,  and  at  Friedensville,  Penn. 

4  The  first  zinc  works  in   the  West  are  said  to  have  been  built  in  the  '50s,  in  Wisconsin, 
by   Georgi,   an   old   Silesian   smelter;   his   undertaking  was   unsuccessful. 


HISTORY     OF     THE     ZINC     INDUSTRY.  15 

In  Missouri  zinc  was  not  made  until  1867,  when  small  works  were  erected 
at  Potosi,  in  Washington  County.  The  Carondelet  works  were  built  in 
1869.  These  works  were  supplied  with  calamine  mined  in  Southeastern 
Missouri.  The  mines  of  the  Joplin  district  became  productive  in  1873, 
their  ores  being  shipped  first  to  the  Illinois  Zinc  Co.  at  Peru,  111.  A  little 
later  zinc  works  were  built  at  Weir  and  Pittsburg,  Kan.,  Eobert  Lanyon, 
who  had  been  engaged  previously  in  zinc  smelting  at  Lasalle,  being  one  of 
the  pioneers  in  Kansas. 

The  zinc  industry  in  the  United  States  has  been  characterized  by  rapid 
development  in  respect  to  production.  The  technical  and  economical  devel- 
opment has  been  slow  on  the  other  hand,  and  up  to  a  few  years  ago  the 
same  type  of  distillation  furnace  was  in  use  as  at  the  time  of  the  inception 
of  the  industry  in  this  country.  The  Wetherill  process  for  the  manufacture 
of  zinc  oxide  directly  from  ores  is  the  most  important  contribution  that  has 
been  made  by  American  engineers  to  the  metallurgy  of  zinc.  Apart  from 
that  the  most  distinctive  feature  in  American  practice  has  been  the  success- 
ful application  of  mechanical  roasting  furnaces  to  the  desulphurization  of 
blende.  About  1895  the  discovery  of  natural  gas  at  lola,  Kan.,  and  the 
location  of  zinc  smelteries  at  that  point  began  a  change  in  the  American 
zinc  industry,  which  has  become  a  radical  one.  In  New  Jersey  also  the 
successful  development  of  the  Wetherill  process  for  the  magnetic  separation 
of  franklinite  and  willemite  has  been  of  great  importance. 


II. 

PEESENT  ECONOMIC  CONDITIONS. 

The  largest  zinc-producing  countries  are  Germany,  Belgium  and  the 
United  States,  which  in  1899  ranked  in  importance  in  the  order  named, 
each  producing  upward  of  100,000  metric  tons  of  spelter.  In  Germany  and 
the  United  States  there  are  in  each  case  two  quite  distinct  zinc-producing 
districts;  in  Germany,  the  eastern,  or  Upper  Silesia,  and  the  western,  or 
Eheinland  and  Westphalia ;  in  the  United  States,  the  eastern  and  southern, 
or  New  Jersey  and  Virginia,  and  the  western,  or  Kansas  and  Missouri,  in- 
cluding the  works  of  Illinois  and  Indiana,  which  derive  their  ores  from  the 
same  source.  Considered  by  districts,  the  rank  in  1900,  with  the  production 
of  each,  was  as  follows:  1,  Belgium,  119,317  metric  tons;  2,  Kansas  and 
Missouri,  104,303  ;*  3,  Upper  Silesia,  102,093 ;  4,  Eheinland  and  Westphalia, 
53,000 ;  and  5,  New  Jersey  and  Virginia,  7,491.  Considered  more  broadly, 
the  production  of  Upper  Silesia  ought  to  be  increased  by  the  output  of 
Poland,  since  the  works  of  that  Kingdom  reduce  ores  mined  from  the  same 
deposits  which  lie  at  the  boundary  between  Eussia  and  Germany  and  extend 
into  each  of  those  empires.  Consequently  the  quantity  of  Silesian  spelter 
produced  is  really  but  little  inferior  to  the  output  of  the  works  of  Belgium. 

Looking  at  the  production  of  zinc  ore  the  largest  producer  is  Germany, 
which  is  followed  in  the  order  named  by  the  United  States,  Italy,  France, 
Spain,  Sweden,  Eussia,  Algeria,  Greece,  New  South  Wales,  Austria,  Great 
Britain,  Belgium,  Tunis,  Turkey  and  Canada.  These  countries,  together 
with  the  neutral  territory  of  Moresnet,  supply  the  entire  consumption  of  zinc 
in  the  world.  Their  ores  may  be  divided  into  two  classes :  ( 1 )  High  grade, 
assaying  over  40%  Zn  before  roasting  or  calcination ;  and  (2)  low  grade,  as- 
saying less  than  40%  Zn.  All  the  ore  of  Poland  (Eussia)  and  Upper  Silesia 
(Germany)  falls  into  the  latter  class,  the  average  grade  of  the  output  in  each 
of  those  countries  being  less  than  30%  Zn.  The  ore  of  Eheinland  and  West- 

1  Including  a  comparatively  small  quantity  The  output  of  the  Joplin  district  alone  is 
of  spelter  produced  from  ore  mined  in  Wis-  still  somewhat  less  than  that  of  Upper 
consin,  Colorado.  Arkansas  and  Tennessee.  Silesia. 

ir, 


.PRESENT   ECONOMIC    CONDITIONS 


17 


phalia  (Germany)  and  the  remainder  of  the  countries  named  is  mostly  high 
grade,  or  rather  it  is  dressed  so  as  to  be  high  grade,  ranging  from  40%  to 
63%  Zn,  though  there  is  very  little  of  it  which  is  higher  than  50%  Zn  out- 
side of  the  United  States.  These  figures  refer  to  the  raw  ores  before  calcina- 
tion, if  they  be  calamines,  or  before  roasting  if  they  be  blendes.  With  respect 
to  the  character  of  the  ore,  the  larger  part  of  the  production  of  Upper  Silesia 
Austria,  Italy,  Greece,  Spain  and  France  is  calamine ;  the  larger  part  of  that 
of  Belgium,  Great  Britain,  Kheinland,  Westphalia,  Sweden  and  the  United 
States  is  blende;  that  of  Poland  is  entirely  calamine;  of  Canada,  blende; 
while  the  entire  output  of  New  South  Wales  is  mixed  blende  and  galena 
from  the  Broken  Hill  mines.  Statistics  of  the  production  of  zinc  and  zinc 
ore  are  given  in  Chapter  IV. 

LIST  OF  EUROPEAN  ZINC  SMELTERS. — Following  is  a  list  of  all  the  zinc 
smelters  of  Europe  who  have  operated  during  the  last  five  years,  together 
with  the  location  of  their  works : 


AUSTRIA. 


Smelters. 


Location  of  Works. 


1  Trifailer  Kohlenwerksgesellschaft 

2  Aerischehutte 

3  Grafliche  Potockische  Berg-  u.  Hutten  Verwaltung... . 

4  Verwaltung der  Hugo  von  Loebbeckeschen  Zinkhutten 

5  Erste  Bohmische  Zinkhutten  u.  Bergbau  Gesellschaft. 
6 


Sagor. 

Cilli. 

Siersza,  near  Trzebinia. 

f  Niedzieliska, 

\  near  Szczakowa. 

Merklin,  near  Pilsen. 
Trzebinia. 


BELGIUM. 


Company. 


Location  of  Works. 


Societe  Anon,  de  la  Vieille  Montagne. 


4G. 


Dumont  et  Freres 

Anon,  de  la  Nouvelle  Montagne 

Anon.  Austro-Belge 

Anon,  metallurgique  de  Prayon 

Anon,  metallurgique  de  Boom 

de  Laminne 

10  Soc.  Anon.  d'Escombrera-Bleyberg 

Soc.  Anon. |des  metaux  d'Overpelt 

12  Soc.  Anon,  des  fonderies  de  Biache  St.  Waast 


5  Soc. 

6  Soc. 

7  Soc. 

8  Soc. 
9L. 


Valentin-Cocq, 

Hollogne-aux  Pierres. 
Angleur  (Chenee). 
Flone,  Hermalle-sous-Huy. 
Sart-de-Seilles,  Seilles. 
Engis. 

Corphalie  lez  Huy. 
Prayon,  a  For6t. 
Boom. 
Antheit. 

Bleyberg,  a  Montzen. 
Overpelt,  near  Neerpelt. 
Ougre"e. 


The  Societe  Anonyme  de  la  Vieille  Montagne  has  also  a  blende  roasting  plant  and 
sulphuric  acid  works  at  Baelen-Wezel.  L.  de  Laminne  has  a  blende  roasting  plant  at 
Ampsin.  Lead  smelteries  are  connected  with  the  zinc  works  at  Bleyberg,  Overpelt  and 

Seilles. 


18 


PRODUCTION    AND   PROPERTIES    OF    ZINC. 
FRANCE. 


Company. 

Location  of  Works. 

Snpi£t£  Anon    (\(*  la  "Vieillp  !Vlonta.firne 

Viviez  (Avevron) 

Compagnie  Royale  Asturienne  des  Mines  

Auby  (Nord). 
St  Amand  lez  Eaux  (Nord) 

^nf»i£t4  HPS  TVTinpQ  dp  IVTalfiflano 

Novelles-Godault 

St.  Jean  de  Losne  (Cote  d'Or) 

GERMANY — UPPER   SILESIA. 


Company. 


Name  and  Location  of  Works. 


Graf  Hugo  Henckelvon  Donnersmarck 

3  Graf  Guido  Henckel  von  Donnersmarck 

4  '• 

5  Herzog  von  TJjest 


7 
8 

9  Grafin  Schaffgotsch 
lOBergwerksgesell.  G.  v.  Giesche's  Erben 

12 

13 

14 O.  S. Eisenbahn-Bedarfs.  Akt.  Gesell.. 

15 

16 

17  H.  Roth 

18 

19 

20  Schles.    Akt.    Gesell.    f.   Bergbau    u. 

Zinkv  uttenbetrieb 

Schles.    Akt.    Gesell.   f.    Bergbau    u. 

Zinkhuttenbetrieb 

22  Schles.  Akt.    Gesell.     f.   Bergbau    u. 

Zinkhuttenbetrieb 

Konigl.  Preuss.  Bergfiscus. 


21 


23 


(Hugohutte)  Antonienhutte. 
(Liebehpffn  ungshiitte)  Antonienhutte. 
(Lazyhutte)  Radzionkau. 
(Guidottohiitte)  Chropaczow. 
(Hohenlohehiitte)  Hohenlohehutte. 
(Fanny  Franzhutte)  Bogutschutz. 
(Carlshutte)  Ruda. 
(Theresiahiitte)  Michalkowitz  II. 
(Godullahutte)  Morgenroth. 
(Wilhelminehutte)  Schoppinitz. 
(Bernhardihiitte)  Rosdzin. 
(Normahiitte)  Normahiitte. 
(Paulshiitte)  Klein  Dombrowka. 
(Beuthenerhutte)  Friedenshutte. 
(Florahiitte)  Bobrek. 
(Rosamundehiitte)  Morgenroth. 
(Kunigundehiitte)  Zawodzie. 
(Clarahutte)  Schwarzwald. 
(Franzhutte)  Bykowine. 

(Silesiahiitte  II)  Lipine. 
(Silesiahutte  III)  Lipine. 

(Thurzohiitte)  Barenhof-Bykowine. 
(Friedrichshiitte )  Friedrichshiitte. 


In  addition  to  the  above  smelteries,  the  Schlesische  Akt.  Gesellschaft  has  a  roasting  and 
sulphuric  acid  plant  (Silesia  IV)  and  a  sulphurous  apid  plant  (Silesia  V)  at  Lipine, 
besides  a  sheet  zinc  rolling  mill  at  the  same  place ;  also  rolling  mills  at  Jedlitze,  near 
Malapane,  at  Ohlau,  and  at  Piela,  near  Rudzinitz.  The  Duke  of  Ujest  has  a  large  rolling 
mill  at  Hohenlohehutte.  The  Bergwerksgesellschaft  G.  von  Giesche's  Erben  has  blende 
roasting  and  acid  works  in  connection  with  the  Bernhardihiitte  and  also  a  separate  plant 
known  as  the  Reckehiitte.  There  are  acid  works  at  the  Lazyhutte  and  Guidottohiitte,  and 
a  zinc  white  factory  at  Antonienhutte. 


PRESENT   ECONOMIC    CONDITIONS. 
GERMANY RHEINLAND  AND  WESTPHALIA. 


19 


Company. 

Location  of  Works. 

Berge-Borbeck. 
Eschweiler. 
Stolberg. 
(  Dortmund. 
\  Stolberg. 
Letmathe. 
Hamborn-Neumuhl. 
Bergisch  -Gladbach. 

Rrheinisch-Nassauischen  Akt  Ge^ellsch'ift    

1  AI<U  o      n   t    f  Bergbau,  Blei.  u.  Zinkhuttenbetrieb  zu 
^  Akt.  (jresell.  f  .  j     stolberg  u.  in  Westphalen  

Markisch-\Vestfalischen  Bergwerksverein     «  • 

Akt  Gesell  f  Zink  Industrie  vormals  W.  Grille 

Aktiengesellschaf  t  Berzelius  .     • 

The  Societe  Anonyme  de  la  Vieille  Montague  has  also  a  blende  roasting  plant,  a  sulphuric 
acid  works  and  a  sheet  zinc  rolling  mill  at  Oberhausen,  Westphalia. 


GERMANY SAXONY. 


Smelter. 

Location  of 
Works. 

Freiberg. 

GREAT    BRITAIN. 


i 

2 
8 

4 

5 

6 

7 
8 
9 
10 
11 

Company. 

Location  of  Works. 

Brunner  IVlond  &  Co  ct 

Winnington. 
Glasgow. 
Swansea  (Llansamlet). 
Swansea  (Port  Tennant). 

Swansea. 

Swansea  (Llansamlet). 
Swansea  (Llansamlet). 
Morriston,  Swansea. 
Netham,  near  Bristol. 
Dynevor,  near  Neath. 
Wavrington. 

Central  Metal  and  Smelting  Co.,  Ltd.  . 
Dillwyn  &  Co  .    .        

English  Crown  Spelter  Co.         

j  Williams.  Foster  &  Co  ) 

j  Pascoe  Grenfell  &  Sons.  ) 

Villiers  Spelter  Co     

Vivian  &  Sons                       « 

Dynevor  Spelter  Co  

H  .  Kenyon  &  Co  b  

a  Make  electrolytic  zinc. 


6  Recover  zinc  from  galvanizers'  waste,  etc. 


ITALY. 


Company. 

Location  of  Works. 

Societa  di  Monteponi  

Monteponi  Sardinia- 

PRODUCTION    AND   PROPERTIES   OF   ZINC. 
NETHERLANDS. 


Company. 

Location  of 
Works. 

Soci<H6  de  la  Campine.  . 

Budel. 
Maestricht. 
Limburg. 

Zinkmaatschappy  in  Lin 

POLAND. 


Company. 

Location  of 
AVorks. 

Bendzin 

D(jrwiz-Szewcow~Pomeranoff  QQ  

Dombrowa 

SPAIN. 


Company. 

Location  of 
Works. 

Arnao  (Asturias) 

LIST  OF  AMERICAN  ZINC  SMELTERS. — In  the  eastern  and  southern  States 
of  the  United  States  there  are  works  in  operation  at  the  present  time,  or 
works  have  recently  been  in  operation,  belonging  to  the  following  concerns : 


1 

1> 

8 

4 
5 
6 

Company. 

Location  of  Works. 

Kind  of  Fuel 
Used. 

Pulaski,  Va  . 

Bitum.  coal. 

Anthracite. 

(i 

i« 

Bitum.  coal. 

Newark,  N.  J  

<i         «          «       it 

Jersey  City  N  J 

ii        <i          (•       « 

So  Bethlehem    Penn 

it        «          ii      ii 

Palmerton    Penn 

Wy  the  Lead  and  Zinc  Co  

Wytheville  Va     

In  the  western  States  there  are  the  following,  many  of  which,  however, 
have  gone  out  of  operation  during  the  last  year  or  two : 


PRESENT   ECONOMIC    CONDITIONS. 


7 
8 
9 
10 
11 
12 
13 
14 
15 
1C 
17 
18 
19 
20 
21 
22 
23 
24 
25 
2H 
27 
28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
31> 
40 
41 

Company. 

Location  of  Works. 

Date  of 
Erection. 

Kind  of 
Fuel  Used. 

Pittsburg.Kan.a.  .  . 
"             "     a.  .  . 
44             4t    a... 
Weir,  Kan.  a  
Nevada  Mo  CL  

1878 
1890 
1891 
1873 
1887 
1891 
1899 
1901 
1886 
1869 
1899 
1881 

1889 
1894 

Bitum.  coal. 

II                      14 
«  1                      II 
II                     II 
It                     It 
II                     li 

Nat.  gas. 
ii      it 

Bitum.  coal. 

«         it 

Nat.  gas. 

Bitum.  coal. 

<«         n 

a         a 

"  d 

Nat.  gas. 
ii      ii 

Bitum.  coal. 
•<         ii 

Nat.  gas. 

<i      ii 

«      <i 

tt      « 

Bitum.coald 

d         tt 

n         « 

Nat.  gas. 
1  1      ii 

Bitum.  coal. 
Nat.  gas. 
Bitum.  coal. 
Nat.  gas. 
Bitum.  coal. 

, 

< 
< 

< 

Cherokee,  Kan.</.  .  . 
lola    Ivjiii.^     

« 

fWtprill     A     R 

«•   ei  

Pnllinflvillp  Zinf*  fJo 

Collinsville,  Ill.o  .  . 
St.  Louis,  Mo.&  .... 

Vd&tir  5^iTio  flo 

Cherry  vale,  Kan.  .  . 

TCvnnirp  55inp  Oo 

*,«                ,4              U 

No.  Chicago,  Ill.c.. 

Peru     111     

Lanyon  Bros.'  Spelter  Co  
Lanyon  S   H    &  Bro  

Neodesha,  Kan.  k.  . 
Pittsburg,  Kan.  a  .  . 
Pittsburg,  Kan.  a  .  . 

1902 
1880 
1882 
1895 
1897 
1898 
1892 
1860 
1899 

1888 
1899 
1899 

1901 
1902 
1899 
1892 

tt         «      « 

<  <          «      n 

«        <t 

t  <          <t      <  < 

La  Harpe  Kan  .... 

Marion  Ind  

Matthie-sen  &  Hegeler  Zinc  Co  — 
Midland  Smelting  Co      •    ........ 

Lasalle  111  

Mineral  Point,  Wis. 
Nevada,  Mo.i   

Nicholson    Greo  E  

it              t< 

lola,  Kan  i  

Prime  Western  Spelter  Co  
Rich  Hill  Mining  and  Smelting  Co. 
United  Zinc  and  Chemical  Co  
United  States  Zinc  Co  

lola,  Kan.  e.  ...  . 
Rich  Hill,  Mo  
lola,  Kan  h  

Pueblo,  Colo.fc  
Upland,  Ind./.  
Wenona,  111     

Vulcan  Spelter  Co  

\Venona  Zinc  Co        ...         .  •  •  • 

a  Idle  (1901).  6  Works  at  Carondelet,  a  district  of  St.  Louis,  c  Works  at  Waukegan,  now  known 
as  North  Chicago,  d  Bituminous  coal  burned  in  gas  producers,  e  Works  at  Gas  City  post-office,  near 
lola.  /These  works  were  built  originally  by  the  Indianola  Zinc  Co.  in  1896;  were  destroyed  by  fire 
and  rebuilt  in  1899.  g  Works  owned  by  the  Cherokee-Lanyon  Spelter  Co..  but  leased  to  and  operated 
by  the  Cherokee  Smelting  Co.  h  Works  built  in  1901  by  the  Standard  Acid  Co..  which  consolidated  In 
1902  with  the  Southwestern  Chemical  Co.,  of  Argentine,  Kan.,  under  the  title  of  United  Zinc  and 
Chemical  Co.  'i  Purchased  by  the  Prime  Western  Spelter  Co.  in  1902.  j  Idle  and  partially  dismantled. 
k  Works  in  course  of  construction  (1902). 


Besides  the  above  list  there  have  been  works,  now  dismantled,  at  Clinton, 
Tenn.  (Edes,  Mixter  &  Heald  Zinc  Co.)  ;  Philadelphia,  Penn.  (Delaware 
Metal  Refining  Co.) ;  Friedensville,  Penn.  ( Friedensville  Zinc  Co.) ;  Bergen 
Point,  N.  J.  (Bergen  Point  Zinc  Co.) ;  St.  Louis,  Mo.  (Missouri  Zinc  Co.) ; 
and  at  Sandoval,  111.  (Swansea  Vale  Zinc  Co.).  Various  of  the  works 


22  PRODUCTION    AND   PROPERTIES    OF    ZINC. 

mentioned  in  the  above  list  have  become  idle  since  it  was  compiled,  besides 
those  which  are  so  indicated. 

The  New  Jersey  Zinc  Co.  was  a  consolidation  (in  1896)  of  the  Lehigh 
Zinc  and  Iron  Co.,  Passaic  Zinc  Co.  and  New  Jersey  Zinc  and  Iron  Co. ;  it 
controls  the  Empire  Zinc  Co.  of  Joplin,  Mo.,  and  North  Chicago,  111.,  and 
the  Mineral  Point  Zinc  Co.  of  Mineral  Point,  Wis.  The  Cherokee-Lanyon 
Spelter  Co.  was  a  consolidation  (in  1896)  of  the  Cherokee  Smelting  and 
Refining  Co.  of  Cherokee,  Kan.,  Eobert  Lanyon  &  Co.,  Pittsburg,  Kan.,  and 
Nevada,  Mo.,  Pittsburg  &  St.  Louis  Zinc  Co.,  Pittsburg,  Kan.,  Scammon 
Zinc  Co.,  Scammon,  Kan.  (works  now  dismantled),  and  Cherokee  Zinc  Co., 
Pittsburg,  Kan.,  and  Weir  City,  Kan.  The  company  also  leased  the  works 
of  the  Girard  Zinc  Co.  and  Kansas  Zinc  Mining  and  Smelting  Co.,  at 
Girard,  Kan.,  which  were  subsequently  returned  to  the  owners  and  sold  by 
them  to  the  Girard  Smelting  Co.;  the  works  of  the  Rich  Hill  Mining  and 
Smelting  Co.,  at  Rich  Hill,  Mo.,  were  also  leased.  The  Lanyon  Zinc  Co. 
was  a  consolidation  (in  1899)  of  the  Robert  Lanyon  Sons  Spelter  Co.  (works 
at  lola  and  La  Harpe,  Kan.)  and  W.  &  J.  Lanyon  (works  at  lola  and  Pitts- 
burg, Kan.).  The  Prime  Western  Spelter  Co.  was  taken  over  in  1902  by 
the  New  Jersey  Zinc  Co.,  and  the  plants  of  A.  B.  Cockerill  and  G.  E.  Nichol- 
son were  purchased  by  it. 

ORE  SUPPLY. — The  zinc  smelters  of  Europe  draw  their  supply  of  ore 
from  the  various  countries  on  the  Continent,  which  have  been  mentioned 
above,  and  to  a  comparatively  small  extent  from  the  United  States,  Canada 
and  New  South  Wales.1  In  Upper  Silesia  and  Westphalia  the  zinc  smelt- 
ers obtain  a  comparatively  small  quantity  of  zinc  oxide,  which  is  recovered 
as  a  by-product  in  smelting  zinkiferous  iron  ores.  The  highest  grade  of  ore 
which  reaches  the  zinc  smelters  of  Europe  is  the  blende  concentrate  from 
Missouri  and  Kansas  and  the  willemite  from  New  Jersey,  which  have  been 
shipped  to  them  during  the  last  three  or  four  years.  The  smelters  of  the 
United  States  use  only  domestic  ores,  the  supply  of  which  is  abundant. 

SYSTEMS  OF  ZINC  SMELTING. — There  are  only  two  systems  of  zinc  smelt- 
ing now  in  use,  namely,  the  Belgian  and  the  Silesian,  which  are  both  based 
on  the  same  general  principles,  but  differ  in  the  types  of  retorts  employed, 
the  furnaces  designed  to  receive  them,  the  grade  and  character  of  the  ore 
that  can  be  treated,  and  the  manner  of  manipulation.  The  primary  differ- 
ence between  the  two  processes  is  the  use  of  comparatively  small  cylindrical 
retorts  arranged  in  several  tiers,  each  with  a  slight  inclination,  in  the  Bel- 

1 A  considerable  quantity  of  the  ore  Swansea,  Wales,  and  Ellesmere  Port,  Eng- 
shlpped  from  New  South  Wales  during  the  land,  by  the  Fry  process,  which  was  aban- 
last  two  or  three  years  was  reduced  at  doned  as  unprofitable  In  1901. 


PRESENT    ECONOMIC    CONDITIONS.  -•> 

gian  process;  and  comparatively  large  muffle-shape  retorts  (commonly  called 
muffles)  set  in  one  tier  in  the  Silesian  process.  A  combination  of  the  two 
processes,  known  as  the  Silesian-Belgian,  or  Rhenish,  is  used  in  some  places, 
chiefly  in  Rheinland  and  Westphalia,  and  to  some  extent  in  Belgium  and 
elsewhere.1  The  Belgian  process  as  used  in  Wales  is  sometimes  called  the 
Welsh-Belgian,  although  it  presents  few  or  no  distinctive  differences.  There 
were  other  methods  formerly  in  use,  the  most  important  among  them  being 
the  English,  in  which  the  zinc  was  reduced  in  pots  and  distilled  downward 
through  a  pipe  in  the  bottom,  and  the  Carinthian,  in  which  a  series  of  short 
vertical  pipes  formed  the  retorts,  but  both  these  were  abandoned  long  ago.2 

The  Silesian  process  is  the  only  one  employed  in  Upper  Silesia  and 
Poland.3  The  smelters  of  Spain  and  the  United  States  use  only  the  Belgian 
process.  Some  of  the  English  and  Welsh  smelters  employ  the  Belgian  and 
some  the  Silesian  process;  in  some  instances  furnaces  of  each  type  are  to 
be  found  in  the  same  works.  The  Silesian-Belgian,  or  Rhenish,  furnace  is 
adopted  generally  by  the  smelters  of  Rhenish  Prussia  and  Westphalia.  In 
Belgium,  the  characteristic  furnace  of  that  country  is  still  the  most  com- 
monly in  use.  The  Silesian  process  was  applied  at  an  early  date  at  two  of 
the  works  of  the  Societe  Anonyme  de  la  Yieille  Montagne  (Valentin-Cocq 
and  Flone)  but  was  eventually  modified  into  what  has  been  herein  desig- 
nated as  the  Rhenish  type ;  similar  furnaces  are  used  at  Viviez,  France,,  but 
with  gas  firing,  while  at  Yalentin-Cocq  and  Flone  direct  firing  is  still 
adhered  to.  During  the  last  few  years  there  has  been  a  marked  tendency 
on  the  part  of  the  Belgian  smelters  toward  a  form  of  Siemens  furnace, 
which  in  some  of  its  features  approximates  to  the  Rhenish  type. 

The  practice  in  the  metallurgy  of  zinc  has  undergone  many  changes  dur- 
ing the  100  years  that  the  industry  has  been  in  existence,  but  the  changes 

1  In  consulting  the  old  hand  books  some  ever  saw   one  in   operation.     According  to 

confusion  will  be  found  as  to  the  classiflca-  Doctor    Percy    they    were    considered    rare 

tion   of  zinc-smelting   processes.        The   old  even    in  1859. 

Silesian  process,  which  is  now  everywhere  *  An  exception  to  this  statement  is  to  be 

abandoned,  was  modified  by  the  introduction  found,   perhaps,   in   the   case  of  the   Hugo- 

of  certain  features   of  the   Belgian   process  hiitte,   at  which   since   1897  all   of  the  old 

and  the  combination  is  referred  to  as  the  furnaces    have    been    replaced    by    Siemens 

Belgian-Silesian     by     some     of     the     older  regenerative  furnaces  with  several  rows  of 

writers    (vide   Kerl,    Grundriss   der   Metall-  small   muffles,   made  by  hydraulic  pressure, 

hiittenkunde).     This    is    the    process    now  At   this   works   a   large   proportion    (up   to 

commonly  employed  in  Upper  Silesia,  which  70%)     of    roasted    blende    is    used    in    the 

I  designate  simply  as  the  Silesian.     On  the  charge.    The  opinion  is  expressed  by  some  of 

other  hand  some  writers  call   the   Silesian  the    Silesian    metallurgists    that,    in    view 

modification  of  the  Belgian  process,  used  In  of  the  diminishing  supply  of  calamine  and 

Rheinland.  Belgian-Silesian.  the    increasing    proportion    of    blende    that 

'Although  the  English  furnace  is  gener-  must  be  distilled,  the  Rhenish  type  of  fur- 
ally  described  in  metallurgical  text-books  naces  will  eventually  replace  the  Silesian  in 
there  are  not  many  living  metallurgists  who  that  Province. 


24  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

have  been  generally  the  result  of  gradual  development  and  never  by  the 
introduction  of  a  radical  innovation.  So  gradual  has  been  the  evolution 
that  many  methods  and  types  of  furnaces  have  remained  quite  unchanged 
through  long  periods  of  years.  Thus,  both  in  Belgium  and  Kansas  there 
are  furnaces  in  use  at  the  present  time  which  in  design  date  back  30  years. 
For  the  successful  distillation  of  zinc  ore  we  appear  to  be  limited  to  com- 
paratively small  retorts;  all  attempts  to  effect  the  distillation  in  blast  fur- 
naces or  otherwise  on  a  large  scale,  save  for  the  production  of  zinc  oxide, 
have  been  failures. 

The  chief  changes  and  improvements  which  have  occurred  in  the  metal- 
lurgy of  zinc  during  the  last  40  years  have  been  the  following : 

1.  ^Replacement  of  calamine  by  blende  as  the  most  important  ore  of  zinc. 

2.  Successful  introduction  of  mechanically-raked  furnaces  for  blende 
roasting,  this  being  especially  a  feature  of  the  improved  American  practice. 

3.  Utilization  of  the  sulphurous  gas  evolved  in  blende  roasting  for  the 
manufacture  of  sulphuric  acid,  which  is  done  to  a  large  extent  in  Germany 
and  Belgium,  to  a  less  extent  in  the  United  States  and  France,  and  recently 
has  been  undertaken  in  Great  Britain.1 

4.  Introduction  of  gas  firing,  with  or  without  heat  recuperation,  espe- 
cially in  connection  with  the  distillation  furnaces,  leading  to  economy  of 
fuel  and  better  extraction  of  zinc  and  permitting  the  construction  of  larger 
furnaces.2 

5.  Manufacture  of  improved  retorts  by  means  of  hydraulic  pressure, 
leading  to  an  increased  extraction  of  zinc  and  ability  to  smelt  more  corro- 
sive mixtures  of  ore. 

6.  Improvement  in  the  sanitary  condition  of  the  furnacemen  by  proper 
control  of  the  fumes,  etc.,  originating  from  the  furnaces;  this  is  a  matter 
which  has  received  a  good  deal  of  attention  in  Belgium,  Germany  and  Great 
Britain,  and  little  or  none  in  the  United  States. 

7.  Introduction  of  labor-saving  devices  for  the  handling  of  material. 

8.  Utilization  of  natural  gas  aa  fuel  in  the  United  States. 

The  most  important  recent  development  in  the  metallurgy  of  zinc  has  taken 
place  in  America,  and  has  been  not  the  result  of  technical  study  and  experi- 
ence, but  the  taking  advantage  of  the  natural-gas  resources  of  Kansas. 

1  The  importance  of  blende  as  a  source  of  gian  works  and  in  Rhenish  Prussia  and 

sulphuric  acid  is  likely  to  increase.  Westphalia  furnaces  with  240  large  retorts 

3  The  tendency  toward  very  large  fur-  are  now  the  standard  size.  Similarly,  in 

naces  has  manifested  itself  most  strongly  Upper  Silesia  the  new  Bernhardihiitte  has 

In  the  United  States,  where  certain  smelters  been  provided  with  Siemens  furnaces  com- 

have  built  them  with  as  many  as  1,008  re-  prising  80  large  muffles,  the  largest  furnaces 

torts.  At  Angleur,  Belgium,  there  are  previously  in  use  in  that  district  having 

ma^sives  with  400  retorts.  At  other  Bel-  had  only  72. 


PRESENT    ECONOMIC    CONDITIONS.  25 

However,  this  has  led  to  such  a  large  reduction  in  the  cost  of  smelting  that 
the  United  States  has  been  placed  in  the  position  where  it  can  frequently 
export  zinc  at  a  profit.  Natural  gas  is  also  used  as  fuel  at  several  smelteries 
in  Indiana,  but  these  are  comparatively  small  works  which  are  less  advan- 
tageously situated  as  to  ore  supply.  The  utilization  of  natural  gas  in  Kan- 
sas and  in  Indiana  has  not  led  to  any  radical  change  in  furnace  type  and 
operation  from  those  fired  with  artificial  gas  elsewhere  in  the  United  States, 
but  it  is  more  economical  inasmuch  as  the  labor  in  handling  coal  to  the  gas 
producers  and  cinder  away  from  them  is  saved,  and  up  to  the  present  time 
the  cost  of  the  natural  gas  has  been  comparatively  insignificant. 

BELGIUM. — The  Belgian  zinc  industry  is  centered  in  the  vicinity  of  Liege, 
where  the  method  of  smelting  which  bears  that  name  originated.  In  this 
district  the  advantages  of  excellent  coal,  superior  fire  clay  and  cheap,  well- 
trained  labor  are  combined.  The  coal  is  mined  near  at  hand  and  the  clay 
has  to  be  transported  only  a  short  distance.  Formerly  these  works  obtained 
their  entire  supply  of  ore  from  domestic  mines,  of  which  the  most  important 
were  situated  at  and  near  the  German  frontier,  but  for  a  good  many  years 
their  output  has  been  insignificant  and  most  of  the  Belgian  spelter  is  now 
smelted  from  foreign  ores,  which  are  imported  chiefly  from  Italy,  Spain, 
Sweden,  Algeria,  Tunis  and  Greece,  being  brought  by  sea  to  Antwerp, 
whence  they  are  shipped  by  rail  or  canal  to  the  works.  The  ocean  freights 
are  low,  and  the  cost  of  carriage  from  Antwerp  to  Liege,  5  fr.  per  2,204-6 
lb..  is  moderate.  The  largest  producer  in -Belgium,  the  Societe  Anonymo 
de  la  Vieille  Montagne,  obtains  a  large  part  of  its  ore  from  its  own  mines, 
which  it  operates  in  many  different  countries.  The  blende  imported  into 
Belgium  is  to  a  considerable  extent  calcined  before  shipment  from  the  mines. 
The  Societe  Anonyme  de  la  Vieille  Montagne  has,  however,  at  Baelen-Wezel 
a  roasting  plant  capable  of  desulphurizing  75,000  metric  tons  of  blende  per 
annum,  to  which  in  1899  a  sulphuric  acid  plant  was  added.  Some  of  the 
other  Belgian  smelters  also  recover  sulphuric  acid,  but  that  operation  in 
connection  with  the  roasting  is  commonly  conducted  in  separate  works  and 
the  ore  is  generally  delivered  to  the  smelteries  in  desulphurized  condition. 

The  Belgian  zinc-smelting  industry  which  was  based  originally  upon  the 
existence  of  the  domestic  supply  of  easily  smeltable  ore  now  rests  chiefly 
upon  the  great  knowledge  of  the  art  accumulated  from  an  experience  of 
nearly  a  century,  the  possession  of  a  large  number  of  thoroughly  trained 
workmen  who  have  been  brought  up  in  the  business  and  the  abundant  supply 
of  excellent  coal  which  exists  in  the  Kingdom.  The  location  of  the  most 
important  zinc  smelteries  of  Belgium  is  shown  by  the  accompanying  map. 

Coal  Resources  of  Belgium. — The  best-developed  portions  of  the  Franco- 


26 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


Belgian  coal-field  occur  within  the  limits  of  Belgium,  the  westerly 
extension  into  France  being  entirely  covered  by  a  great  thickness  of  newer 
strata.  Commencing  at  the  eastern  side,  the  first  basin  is  that  of  Liege, 
which  extends  from  the  Prussian  frontier  near  Verviers  in  a  southwesterly 
direction  for  about  45  miles,  the  greatest  breadth  being  about  nine  miles, 
near  Liege.  The  principal  working  points  are  concentrated  on  the  western 
edge.  The  number  of  seams  is  83.  The  uppermost  series  of  31  affords  fat 
coals,  suitable  for  coking;  the  middle  series  of  21  seams  yields  semi-dry  or 
flaming  coals;  while  the  lowest  series  of  31  seams  consists  of  lean,  or  semi- 
anthracite  coal. 

The  uppermost  series  of  seams,  which  are  the  most  valued,  is  found  only  in 


FIG.  1. — MAP  or  PORTIONS  OF  BELGIUM,  FRANCE,  HOLLAND  AND 
EHENISH  PRUSSIA. 

Scale :  1  in.  =  40  miles. 

a  small  area  near  the  center  of  the  basin  at  Ougree,  near  Liege.  The  seams 
vary  from  6  in.  to  5-5  ft.  in  thickness,  the  average  being  barely  3  ft.  The 
same  order  of  succession  is  observed  in  all  the  coal  districts  along  this  axis. 
The  strata  have  a  comparatively  small  slope  on  the  northern  outcrop,  and 
are  sharply  contorted,  faulted,  or  broken  on  the  south  side  of  the  basins. 
The  next  basin,  that  of  the  Sambre,  extends  for  about  30  miles  from  Namur 
to  Charleroi,  the  greatest  exposed  breadth  being  about  9-5  miles.  At  Mont- 
ceau,  near  Charleroi,  there  are  73  seams.  The  most  important  development 
of  the  coal  measures  in  Belgium  is  in  the  basin  of  Mons,  which  extends  from 
Mons  to  Timlin,  a  distance  of  about  14  miles,  with  a  breadth  of  about  seven 


PRESENT    ECONOMIC    CONDITIONS. 


27 


or  eight  miles.  The  number  of  known  coal  seams  is  157,  of  which  from  117 
to  122  are  workable,  their  thickness  varying  generally  between  10  and  28  in., 
only  a  few  exceeding  3  ft.  They  are  classified  into  the  following  groups: 

1.  Upper  series  (cliarbon  flenu),  47  seams,  which  occur  chiefly  in  the 
neighborhood  of  Mons :  These  are  the  most  highly  bituminous  coals  that  are 
found  in  Belgium. 

2.  Hard-coal  series  (charbon  dur),  21  seams:     These  are  soft,  coking 
coals,  less  rich  in  volatile  matter  than  the  flenu,  but  excellent  for  coking. 

3.  Forge-coal  series,  29  seams:  These  are  chiefly  used  for  smithy  pur- 
poses and  ironworks,  but  the  lower  members  approximate  to  dry  steam  coals. 

4.  Dry  or  lean  coals,  20  to  25  seams,  forming  the  bottom  series :  They  are 
of  small  value,  being  used  chiefly  for  brick  and  lime  burning. 

The  Belgian  coal  available  to  the  zinc  smelters  is  only  semi-fat  in  char- 
acter and  direct  firing  is  still  maintained  to  a  large  extent  at  the  Belgian 
smelteries.  Such  Belgian  works  as  have  adopted  gas  firing  are  obliged  to 
import  German  coal.  The  Societe  Anonyme  de  la  Vieille  Montagne  has 
always  sought  to  use  at  its  works  the  coal  most  easily  obtained  and  conse- 
quently in  order  to  avoid  recourse  to  foreign  coal  retains  direct  firing  for 
the  more  part  of  its  furnaces  in  Belgium,  although  it  is  admitted  that  gas 
firing  is  more  advantageous  than  direct,  when  suitable  coal  is  available.1 

Cost  of  Coal  in  Belgium. — The  cost  of  Liege  coal  delivered  at  the  works 
near  Liege  in  1893  was  10@11  fr.  (approximately  $2@$2-20)  per  1,000 
kg.  (2,204-6  lb.).  Since  then  and  especially  during  the  last  two  or  three 
years  the  cost  has  increased  greatly,  with  the  result  that  the  profits  of  the 
Belgian  zinc  smelters  have  been  seriously  diminished,  notwithstanding  the 
increase  in  the  market  price  of  spelter  in  Europe  during  the  same  period. 
The  Societe  Anonyme  de  la  Vieille  Montagne  submitted  to  its  stockholders 
the  following  data  as  to  the  cost  of  the  coal  used  at  its  works  in  Belgium, 
France  and  Germany  from  1896  to  1900,  both  years  inclusive. 


Year. 

Metric  Tons. 

Cost,  Francs. 

Average  per 
Ton,  Francs. 

1896 

430,491 

4  529  087  •  49 

10-52 

1897  

443.746 

4,954,975  68 

11*17 

1898  

458.074 

5,459  272  '75 

11'92 

1899 

471  285 

6  414  165'81 

13  '61 

1900  

494,945 

8,469,377  '07 

17'11 

The  largest  part  of  the  above  consumption  of  coal  occurred  in  the  Belgian 
works  of  the  company.     The  average  cost  of  the  coal  used  there  was  as 


1 M.   Gaston  de  Sinc.ay,  director  general   of  the  Societe  Anonyme  de  la  Vieille  Montagne, 
in  The  Mineral  Industry,  VIII,  655. 


28  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

follows :  1896,  9-96  fr. ;  1897,  10-66 ;  1898,  11-71 ;  1899,  13-75 ;  1900,  18-19. 
At  the  end  of  1900  contracts  for  a  part  of  the  requirements  of  the  company 
were  renewed  at  22  fr.  per  metric  ton.  Not  merely  has  the  price  of  coal 
risen,  but  also  its  quality  has  deteriorated,  necessitating  a  larger  consump- 
tion to  do  the  same  work.  The  increase  in  the  cost  of  coal  in  1900  as  com- 
pared with  1899  was  equivalent  to  18-27  fr.  per  share  of  the  capital  stock  of 
the  Societe  Anonyme  de  la  Vieille  Montagne,  which  was  not  offset  by  the 
increased  value  of  the  zinc  produced,  the  average  realized  per  metric  ton  of 
crude  spelter  in  1900  having  been  only  503-2  fr.  against  616-5  in  1899. 

Cost  of  Fire  Clay. — The  fire  clay  required  for  the  manufacture  of  re- 
torts, condensers  and  other  refractory  material  is  obtained  chiefly  from 
Andennes.  In  1893  it  cost  12@13  fr.  ($2-40@$2-60)  per  1,000  kg.  deliv- 
ered at  or  near  Liege. 

Cost  of  Labor. — The  average  wages  for  labor  at  the  Belgian  zinc  smelt- 
eries are  about  3-5  fr.  ($0-70)  per  day,  the  maximum,  paid  to  foremen,  etc., 
being  6  fr.  ($1-20)  per  day.  The  rate  of  wages  has  increased  greatly  dur- 
ing the  development  of  the  zinc  industry  in  Belgium.  In  1887  the  average 
at  Anglcur  was  3-15  fr.  ($0-63)  ;  in  1837  is  was  only  1-35  fr.  ($0-27). 

Statistics  of  the  Belgian  Zinc  Industry. — In  1895  there  were  10  zinc 
smelters  in  Belgium,  having  330  furnaces  in  operation  and  58  idle,  with 
an  average  of  25,609  retorts  in  operation.  These  works  had  81  steam 
engines,  an  aggregate  of  2,442  h.  p.,  and  employed  4,470  men,  who  received 
an  average  daily  wage  of  3-51  fr.  There  were  smelted  12,842  metric  tons  of 
Belgian  ore  and  214,947  tons  of  imported  ore,  requiring  504,357  tons  of  coal 
and  producing  96,944  tons  of  spelter,  worth  356-86  fr.  per  ton.  Of  the 
spelter  product,  34,081  tons  were  rolled  into  sheet  at  an  expense  of  13,616 
tons  of  coal  and  the  labor  of  477  men,  who  received  an  average  wage  of  3-77 
fr.  per  day.  The  average  value  of  the  sheet  zinc  produced  was  394-41  fr.  per 
ton.  The  number  of  zinc  works  in  operation  in  Belgium  in  1897  was  nine, 
there  being  only  one  inactive  plant.  The  active  works  had  359  furnaces 
with  a  total  of  27,827  retorts.  The  inactive  plant  had  68  furnaces.  The 
total  number  of  men  employed  was  4,820,  who  received  an  average  daily 
wage  of  3-49  fr.  The  consumption  of  coal  was  547,666  tons.  Of  Belgian 
ore  14,636  tons  were  smelted;  of  foreign  ore  250,016  tons.  The  production 
of  spelter  was  103,885  tons,  valued  at  427-41  fr.  per  ton.1  In  1898  the 
quantity  of  ore  smelted  in  Belgium  was  291,977  tons,  of  which  13,295  was 
from  domestic  sources  and  the  remainder  was  imported. 

1  British  Foreign  Office,  Report  No.  484,  production  of  spelter  in  1897  was  116,067 
Miscellaneous  Series,  November,  1898.  Ac-  metric  tons,  and  in  1895  it  was  107,664 
cording  to  the  Belgian  official  statistics  the  tons. 


PRESENT    ECONOMIC    CONDITIONS. 


29 


Character  of  Ore  Smelted. — The  diverse  sources  of  the  ore  smelted  at 
Belgian  works  is  shown  by  the  statistics  for  1898,  in  which  year  59,118  tons 
were  obtained  from  Sardinia;  48,101  from  France;  34,973  from  Sweden; 
x>0,076  from  Algeria ;  and  17,552  from  Germany.  Besides  the  domestic  pro- 
duction, additional  supplies  of  ore  were  obtained  from  Greece,  Australia, 
the  Italian  mainland,  England,  Tunis,  Turkey,  Austria  and  the  United 
States.  Analyses  of  ores  received  by  Belgian  smelters  from  various  sources 
in  1898,  which  illustrate  the  nature  of  their  ore  supplies,  are  given  in  the 
following  table: 

ANALYSES  OF  ORES  BOUGHT  BY  BELGIAN  SMELTERS  IN  1898.a 


Kind  of  Ore. 

Source. 

%  Zn 

%  Pb 

%Fe 

Mn 

%  S 

%CaO 

%MgO 

%  Cd 

%  Ag 

%SiO. 

Raw  blende    6 

Calcined  calamine    .  .  c 
Roasted  blende    d 
Calcined  calamine  .  .  e 

Raw  blende  e 
Roasted  blende  

Belgium  
Sardinia  

35-00 
40-00 
54-00 
50-20 
51-00 
53-00 
50-55 
49-50 
50-00 
61-84 
59-80 
60-40 
37-00 
41-00 
40-00 
33*50 
39-12 
56-10 
56-88 
33-00 
30-40 
39-50 
35-10 
35-00 
32-00 
34-00 
57-00 
46-00 
44-00 
53-00 
46-00 
49-00 
55*00 
35-00 
47-00 
37-00 
35-00 
34-00 
38-00 
24-00 
42-00 
48-50 

tr. 
9-00 
3-00 
5'20 
9-00 
12-00 
10-33 
9-00 
12-00 
11-44 
0-25 
13-40 
9-00 
2'73 
2-00 
4'50 
8-13 
5'50 
4-50 
tr. 
1-30 
8'50 
12'16 
8-30 
2-00 
2-40 
1'80 
6-00 
4*00 
4-00 
4-50 
6-00 
11-50 
5-00 
4-00 
14-00 
13-00 
5-50 
13-50 
6-00 
8-00 
7'50 

12-66 

7:70 

31-00 
32-00 

2:80 

2-00 

0-80 

tr. 

o-ooi 

3-00 

0-16 

0'42 

0'020 

15-50 

France  

7'00 
8-61 

'4:66 
1-74 
2-83 
1-75 

10-00 

3-99 
7'00 

'7:66 

2'52 
4-64 

21:  50 
18-00 
2'68 
0-93 
? 
23-00 

32:66 
1-22 
2'50 
2-20 

1-50 
3-30 

0-80 
2-95 

0'15 

0*018 

3-00 
2-75 

« 

it 

"       

2-00 
0-65 
1-20 
0-72 

i-oo 

0-14 

o-ooi 

2-50 
1-00 
15'46 
1-50 

10-00 

33-97 

o-io 

<(       

'6:4o' 

1'50 
2:66' 

'  tr.'  ' 
0-015 

6:6o7 
o:66e 

Raw  blende  
Calcined  calamine  .... 

Raw  blende  / 
Crude  calamine 

Sweden    
Spain 

5-90 
5'00 

Algeria  

0-60 
2-44 
0-65 

tr. 
0-45 
0-40 

12'15 
11-00 
12-65 

Roasted  blende  

0-005 

Greece  .          .    . 

Calamine  g 

24-29 
20-72 
13-80 
12-60 
6-00 
2-50 
7-50 
5  '00 
8-00 
3'5U 
4-50 
7-00 
5-50 
11-50 
8-50 
6-50 
8'50 

10-00 

7-00 
5-00 
7-00 
9'20 

'2:80 
2-43 
? 

14-50 
1-80 
tr. 
20-00 
0-50 
0'60 
0-50 
0-80 
30-00 
28-00 
22-00 
23-00 
18-00 
23-00 
19-00 
21-00 
3'40 

10-85 
2-30 
0-65 
2-42 
4-00 
4-50 
1-10 
4-50 
9-00 

13 

9 
3 
2 
2 
11 
7 
1 
0 
6 
0 
4.17 

1-80 

...  . 

6:6io 

0-040 

0:004 
0-004 

4-00 
3-80 
18-50 
20-60 
15-00 
28-00 
4-00 
8-00 
8*00 
ll'OO 
7*00 
7-00 
3-00 
11  50 
6-50 
3-00 
8-00 
17-50 
14  00 
34-00 
13-50 
11-80 

Roasted  blende  h 

« 

Australia  

0-20 
1-10 
1'50 
0-50 
0-40 
1-50 
1-50 

•oo 
•oo 
•oo 

•50 

•oo 
•oo 

•50 
•50 
•25 
'65 

•oo 

•70 
1.10 



Calamine     
Raw  blende  
Roasted  blende  
Calcined  calamine.  .  .  . 
Raw  blende 

Italy  

Great  Britain  . 
Austria  

0-080 

6:ie' 
0-11 

0-20 
0'30 
0-15 
0-35 
0-08 
0-03 
0-08 
0'12 

o-io 

0-17 

tr. 

o-ooi 

0'012 
J-011 

0-011 

0-020 
0*090 
0-070 
O'Oll 
0*040 
0-025 
0-050 
0-060 
O'Oll 

Calcined  calamine  .  .  . 

.  .  t 
''          •  .  ? 
Raw  blende                 A: 

Not  stated  

.1 

m 
,.n 

0 

p 

g 
Roasted  blende  r 

a  Compiled  from  data  in  a  paper  by  Ad.  Firket  in  Annales  des  Mines  de  Belgique,  VI,  i  and  it 
5  Gangue.  calcareous,  silicious  and  ferruginous,  c  Gangue,  silicious  and  ferruginous,  d  This  sample 
also  contained  0'40%  Sb.  e  Gangue,  silicious  and  ferruginous.  /This  sample  contained  a  little  CaCO3 
and  a  good  deal  of  iron.  0Also  contained  SiOa,CaO  and  much  FeaOs.  h  Also  contained  0'4%  Cu. 
i  Also  contained  0-01%  As.  j  Also  contained  0-009%  As.  k  Also  contained  0-07%  As  and  0-2%  Sb. 
i  Also  contained  0-10%  Sb.  m  Also  contained  0-042%  As.  »  Also  contained  0-79%  As.  o  Also  contained 
0-011%  As.  p  Also  contained  0'17%  Sb.  q  Also  contained  0-02%  Sb.  r  Average  of  roasted  blende 
bought  by  a  certain  works. 


30  PRODUCTION  AND  PROPERTIES  OF  Z1XC. 

The  assa}7s  of  numerous  Sardinian  ealamines  received  by  Belgian  smelters 
in  1898  will  be  found  in  Chapter  X.  M.  Firket  has  computed  that  the 
entire  quantity  of  ore  reduced  in  Belgium  in  1898  averaged  about  45-48% 
Zn  and  4-35%  Pb,  which  figures  it  should  be  remembered  refer  to  calcined 
calamine  and  roasted  blende  and  not  to  raw  ores. 

FRANCE. — This  Eepublic  is  a  large  producer  of  zinc  ore  and  of  spelter. 
The  industry  is  rather  scattered,  however,  instead  of  being  concentrated  at 
a  few  points,  and  the  French  zinc  ore  is  largely  exported  to  other  countries 
for  reduction,  chiefly  to  Belgium,  while  the  French  smelters  derive  their  sup- 
ply chiefly  from  Greece,  Sardinia  and  Spain.  The  most  important  zinc 
smelteries  in  France  are  those  at  Auby  (Nord)  belonging  to  the  Compagnie 
Eoyale  Asturienne  des  Mines,  and  at  Viviez,  in  Aveyron,  belonging  to  the 
Societe  Anonyme  de  la  Vieille  Montagne.  The  latter  company  has  also  a 
rolling  mill  at  Panchot  in  Aveyron.  There  is  a  smeltery  belonging  to  the 
Societe  de  Mines  de  Malfidano,  at  Noyelles-Godault,  where  some  of  the  ore 
from  the  Sardinian  mines  of  that  company  is  reduced.  A  zinc  smeltery  was 
also  established  at  St.  Amand,  Xord,  in  1896. 

The  conditions  governing  the  zinc-smelting  industry  in  the  north  of 
France  are  quite  similar  to  those  in  Belgium,  the  Belgian  coal  fields  extend- 
ing through  that  portion  of  France.  As  in  Belgium  the  coal  is  only  semi- 
fat  and  direct  firing  is  still  generally  maintained.  At  the  works  of  the 
Societe  Anonyme  de  la  Vieille  Montagne  in  Aveyron,  in  the  south  of  France, 
however,  a  coal  containing  38%  of  volatile  matter  is  available  and  gas  firing 
is  employed  with  considerable  economy  as  compared  with  direct  firing.  In 
France  as  in  Belgium  the  value  of  coal  has  risen  greatly  during  the  last  five 
years,  the  average  cost  of  the  consumption  at  the  French  works  of  the  Societe 
Anonyme  de  la  Vieille  Montagne  having  been  as  follows :  1896,  9-62  fr.  per 
metric  ton;  1897,  9-99  fr.;  1898,  10-14  fr.;  1899,  10-94  fr.;  1900,  11-63  fr. 

GERMANY. — The  zinc  smelters  of  Germany  fall  into  two  distinct  divisions, 
namely,  the  western,  or  Ehenish,  and  the  eastern,  or  Silesian.  Outside  of 
these  there  is  only  one  small  works  at  Freiberg,  in  Saxony,  the  production 
of  which  is  insignificant. 

Rhenish  Prussia. — The  eight  zinc  smelteries  of  Ehenish  Prussia  are 
divided  into  two  groups,  three  in  the  Ehine  Province,  near  the  Belgian 
frontier  on  the  west  side  of  the  Ehine,  and  five  in  Westphalia,  east  of  the 
Ehine.  The  former  group  comprises .  the  works  at  Eschweiler  and  Stol- 
berg,  near  Aachen  (Aix-la-Chapelle)  ;  the  latter  includes  the  works  at 
Berge-Borbeck  near  Essen,  Dortmund,  Letmathe,  Hamborn,  and  at 
Bergisch-Gladbach  near  Cologne.  Practically  the  same  conditions  exist 
in  both  sections  of  the  Ehenish  district. 


PRESENT   ECONOMIC    CONDITIONS.  31 

Coal  Resources  of  Rhenish  Prussia  and  Westphalia. — The  coal  fields  of 
Rhenish  Prussia  and  Westphalia,  situated  on  the  extension  of  the  Franco- 
Belgian  axis,  are  the  two  small  basins  of  the  Inde  and  Worm,  east  of 
Adelnau,  near  Stolberg  and  Eschweiler,  and  the  great  Westphalian  basin  east 
of  the  Rhine,  in  the  valley  of  the  Ruhr.  The  last,  which  is  one  of  the  most 
important  in  Europe,  extends  for  about  30  miles  east  and  west  from  Essen 
to  Dortmund.  Its  breadth  is  unknown;  the  beds  are  exposed  for  about  15 
miles  at  the  widest  part,  but  the  actual  boundaries  to  the  north  and  north- 
east are  hidden  by  Cretaceous  rocks.  The  greatest  depth  from  the  surface 
to  the  bottom  of  the  basin  is  probably  about  5,000  ft.  It  is  divided  length- 
ways by  transverse  axes  of  elevation  into  four  principal  basins,  besides  sev- 
eral smaller  ones.  The  total  thickness  of  measures  so  far  as  proved  is  from 
0,000  to  8,000  ft.,  with  about  130  seams  of  coal,  altogether  about  300  ft. 
thick.  These  are  divided  into  three  series  by  two  bands  of  barren  measures. 
The  thickness  of  the  individual  coal  seams  varies  from  8  in.  to  7  ft.  Sev- 
enty-six are  considered  to  be  workable,  having  a  combined  thickness  of  205 
ft.,  and  54  are  unworkable,  containing  42  ft.  of  coal.  The  proportion  of 
workable  coal  to  the  whole  thickness  of  strata  is  as  1  :  33.  The  order  of 
succession  as  regards  quality  is  similar  to  that  observed  in  Belgium,  the  most 
highly  valued  gas  and  coking  coals  being  at  the  top  of  the  series,  and  the 
dry  semi-anthracite  seams  at  the  bottom.  There  is  an  abundant  supply  of 
the  fat  coal  and  gas  firing,  with  or  without  heat  recuperation,  is  now  gener- 
ally adopted  by  the  zinc  smelters  of  Rhenish  Prussia  and  Westphalia. 

At  Stolberg  the  coal  for  heating  the  furnaces  cost  about  10  marks  ($2-38) 
per  1,000  kg.  in  1893,  while  reduction  material  (hard-coal  fines  from  the 
washeries)  was  obtainable  for  about  five  marks.  Since  that  time  the  cost  of 
coal  in  Rheinland  and  Westphalia  has  risen  materially,  especially  during  the 
last  two  or  three  years,  though  not  to  so  great  an  extent  as  in  Belgium.  The 
Societe  Anonyme  de  la  Vieille  Montagne  has  reported  the  average  cost  per 
metric  ton  of  the  coal  consumed  in  its  Westphalian  works  as  follows :  1896, 
10-13  fr.;  1897,  10-68;  1898,  10-82;  1899,  11-44;  1900,  12-41. 

Labor,  Ore  and  Refractory  Materials. — The  Rhenish  works  have  to 
import  from  Belgium  the  fire  clay  needed  for  the  manufacture  of  their 
retorts.  In  1893  it  cost  them  about  12  marks  ($3)  per  metric  ton.  Wages  are 
about  the  same  as  in  Belgium,  common  labor  being  paid  two  marks  (47-6c.) 
per  day  at  Stolberg,  and  furnace  men  four  marks  (95-2c.).  The  Rhenish 
smelters  import  a  part  of  their  ore  supply  from  foreign  countries,  via  Ant- 
werp and  Rotterdam,  from  which  ports  they  are  not  far  distant,  but  they  ob- 
tain the  more  part  from  domestic  sources,  the  mines  near  the  Belgian  fron- 
tier and  in  Westphalia  being  still  very  productive,  while  considerable  quanti- 


32  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

ties  are  also  derived  from  the  Harz,  and  Friedrichssegen  and  elsewhere  in 
Nassau.  The  Grille  works  at  Hamborn  have  been  lately  receiving  a  consid- 
erable quantity  of  New  Jersey  willemite,  which  is  used  for  making  a  high- 
grade  spelter.  The  Societe  Anonyme  de  la  Vieille  Montagne  operates  on  a 
large  scale  the  mines  at  Bensberg,  near  Cologne,  on  the  east  side  of  the 
Ehine,  producing  blende  which  is  roasted  at  Oberhausen,  where  sulphuric 
acid  is  manufactured  from  the  roast  gases,  the  desulphurized  ore  being 
smelted  subsequently  at  Berge-Borbeck,  near  Essen.  Eecently  the  produc- 
tive capacity  of  the  Bensberg  mines  has  been  largely  increased,  a  new  dress- 
ing works  having  been  erected  there  in  1898. 

Silesia. — The  Silesian  zinc  district  lies  entirely  within  what  was  once 
Poland,  but  is  now  partitioned  among  Eussia,  Austria  and  Germany,  the 
dividing  line  between  Eussia  and  Germany  crossing  the  zinc-bearing  forma- 
tion. The  larger  part  of  the  deposit  lies,  however,  in  Germany.  The  center 
of  the  district  is  Beuthen,  a  small  city  in  the  corner  of  the  province  of  Ober- 
schlesien  (Upper  Silesia),  only  a  few  kilometers  from  the  Eussian  and  Aus- 
trian frontiers.  Next  in  importance  is  the  town  of  Kattowitz.  The  23 
smelteries  of  Prussian  Silesia  are  situated  near  those  places.  Just  over  the 
line  in  Poland  there  are  works  at  Bendzin  and  Dombrowa,  and  in  Austria 
(Galicia)  at  Siersza,  Medzieliska  and  Trzebinia. 

Coal  Resources  of  Silesia. — The  coal  fields  of  Silesia  are  the  most  im- 
portant of  eastern  Europe.  Those  of  Lower  Silesia  and  Bohemia  form  a 
basin  between  Glatz,  Waldenburg,  Landshuet,  and  Schatzlar,  about  38  miles 
long  and  22  miles  broad.  The  number  of  seams  from  3-5  to  5  ft.  thick  is 
between  35  and  50,  but  it  is  difficult  to  trace  any  one  continuously  for  a 
great  distance.  The  lower  seams  usually  lie  at  a  higher  angle  than  those 
above  them.  There  does  not  appear  to  be  any  relation  between  the  character 
of  the  coals  and  their  geological  position,  and  the  same  seam  often  varies  in 
quality  in  neighboring  mines. 

The  Upper  Silesian  coal  field  extends  in  several  disconnected  areas  from 
Maehrisch-Ostrau  in  Moravia,  in  a  northwesterly  direction,  by  Eybnik  and 
Gleiwitz  in  Prussia,  and  Myslowitz  in  Poland,  lying  partly  in  Austria,  Prus- 
sia and  Eussia.  The  Prussian  portion  between  Zrabze  and  Myslowitz  is  the 
most  important,  extending  over  20  miles  in  length,  by  nearly  15  in  breadth. 
The  greatest  thickness  of  coal  in  workable  seams  (which  vary  from  2-5  to  60 
ft.  in  thickness)  is  estimated  at  a  total  of  333  ft.,  the  thickness  of  the  meas- 
ures being  about  10,000  ft. 

The  great  coal  measures  of  Upper  Silesia  exist  in  close  proximity  to  the 
zinc  mines,  as  may  be  seen  from  the  map  on  page  215,  and  the  smelters 
are  favored  consequently  not  only  by  comparatively  cheap  coal  of  very  good 


FUKSKNT    ECONOMIC    CONDITIONS. 


33 


quality,  but  also  by  low  cost  of  carriage  of  the  ore  to  it,  which  is  of  more 
importance  in  this  district  than  elsewhere  on  account  of  the  low  grade  of 
the  ore.  The  best  coal  in  1893  cost  about  eight  marks  ($1-92)  per 
1,000  kg.  at  the  smelteries,  from  which  figure  the  price  ranged  downward 
to  about  2  (a  4  marks  for  the  inferior  grades  which  are  used  to  a  large  ex- 
tent. Since  1898  the  Silesian  coal  has  appreciated  a  good  deal  in  value,  but 
not  in  so  great  a  proportion  as  has  been  experienced  in  Belgium.  Accord- 
ing to  the  statistics  of  the  Oberschlesischen  Berg-  und  Huttenmannischen 
Yereins  the  average  value  per  1,000  kg.  of  the  entire  production  of  coal  in 
Tapper  Silesia  at  the  mines  has  been  as  follows : 


Year 

Mark*. 

Year 

Marks 

Year 

Marks 

I 
Year 

Marks 

1886 
1887 
1888 
1889 

3-688 
3-550 
3-550 
3-730 

1890 
1891 
1892 
1893 

4-800 
5'415 
5-437 
5*371 

1894 
1895 
1896 
1897 

5-228 
5-197 
5'216 
5'319 

1898 
1899 
1900 
1901 

5-585 
6-005 
7-133 

These  figures  represent  the  average  of  all  kinds  of  coal  produced — i.e., 
they  may  be  assumed  as  indicating  the  value  of  the  run  of  the  mine.  The 
Silesian  zinc  smelters  use  chiefly  small  sizes  and  slack  for  heating  their 
furnaces.  The  relative  value  of  the  different  sizes  of  coal  in  1891  was  as 
follows:  Xo.  1,  7@8-5  marks;  Xo.  2  (about  nut  size),  5@5-5  marks; 
Grieskohl,  3@4  marks;  dust-coal  (under  10  mm.  size),  1-6(5)2  marks. 

'Labor,  Ore  and  Refractory  Material. — Refractory  material  costs  consid- 
erably more  in  Silesia  than  in  either  Rhenish  Prussia  or  Belgium;  how- 
ever, the  consumption  is  less  per  ton  of  ore  smelted.  The  best  fire  clay  is 
imported  from  Briesen,  in  Moravia  (Austria),  and  costs  30  marks  ($7-20) 
per  1,000  kg.  (2,204-6  Ib.) ;  other  Moravian  clay  is  obtained  for  22  marks 
($5-28);  while  ordinary  Silesian  clay  is  worth  15  marks  ($3-60).  The 
wages  for  labor  are  about  the  same  as  in  the  west  of  Germany,  the  best  class 
receiving  3@4  marks  ($0-72@$0-96)  per  day,  but  a  larger  proportion  of 
cheaper  labor  is  used,  women  who  are  paid  only  0-90@1-20  marks  ($0-22@ 
$0-29)  per  12  hours  being  employed  for  much  of  the  common  work,  such  as 
dressing  the  ore  and  sorting  old  refractory  material.  The  employment  of 
women  in  the  smelting  houses  has  been  recently  discontinued,  however,  in 
some  of  the  largest  plants  of  the  Province,  namely  those  of  the  Duke  of  TJjest. 
The  working  population  of  Upper  Silesia  is  mostly  (90%)  Polish. 

The  ore  supply  of  the  Silesian  smelters  is  obtained  chiefly  from  the  local 
mines  and  consists  of  both  calamine  and  blende.  The  Polish  works  use 
only  calamine,  which  is  very  low  in  grade.  In  Upper  Silesia  the  proportion 


34  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

of  blende  to  calamine  is  steadily  increasing.  The  Silesian  smelters  are 
receiving  considerable  quantities  of  blende  (roasted)  from  Sweden  and 
Styria  (Austria).  The  Silesian  ores  generally  contain  lead,  and  the  spelter 
derived  from  them  contains  so  much  of  that  impurity  that  it  has  to  be 
subjected  to  a  refining  process.  Numerous  analyses  of  the  ores  smelted  in 
Upper  Silesia  will  be  found  in  Chapter  X. 

GREAT  BRITAIN. — The  chief  center  of  the  British  smelting  industry  is  at 
Swansea,  in  Wales,  where  an  abundant  supply  of  extremely  high-grade  coal 
is  available  and  a  considerable  quantity  of  ore  is  obtainable  from  mines  in 
Wales,  which  are  described  in  Chapter  X.  These  mines  formed  the  basis  of 
the  original  Welsh  smelting  industry,  but  their  production  has  for  a  long 
time  been  inadequate  to  meet  the  requirements  of  the  Swansea  smelters,  who 
have  therefore  had  to  draw  their  supplies  from  other  countries,  chiefly  Italy 
and  Spain,  and  lately  to  some  extent  from  the  United  States.  Swansea 
being  an  important  seaport,  the  zinc  smelters  at  that  place  are  situated  favor- 
ably with  respect  to  obtaining  ore  from  all  countries  whence  it  would  natu- 
rally be  shipped  by  sea. 

Coal  and  Fire  Clay. — The  coal  used  for  heating  the  furnaces  cost  the 
Welsh  smelters  7s.  6d.  per  ton  of  2,240  Ib.  in  the  midsummer  of  1899 ; 
anthracite  fine  coal  for  reduction  material  cost  4s.  per  ton.  The  best  Stour- 
bridge  fire  clay  cost  60s.  per  ton.  These  prices  for  coal  and  fire  clay  repre- 
sented the  cost  of  those  materials  delivered  at  the  works.  It  will  be  seen  that 
the  cost  of  coal  to  the  Welsh  smelters  is  less  than  to  the  Belgian  and  Ehenish 
smelters,  but  is  rather  high  as  compared  with  the  cost  to  American  smelters ; 
it  must  be  pointed  out,  however,  that  the  Welsh  coal  is  far  superior  in  heat- 
ing value  to  any  bituminous  coal  which  is  used  by  American  zinc  smelters, 
and  there  is  probably  no  great  difference  between  Welsh  coal  at  7s.  6d.  per 
2,240  Ib.  and  Kansas,  Missouri,,  or  Illinois  coal  at  $1  per  2,000  Ib. 

Wages. — The  wages  of  labor  at  Swansea  are  low  as  compared  with  Ameri- 
can conditions  and  high  as  compared  with  the  Continental.  Common  labor 
is  paid  from  3s.@3s.  6d.  per  day.  Furnacemen  are  paid  as  follows:  First 
hand  6s.,  second  hand  5s.,  third  hand  4s.,  all  per  shift  of  12  hours. 

Furnaces. — The  Welsh  smelters  formerly  employed  chiefly  the  Silesian 
type  of  distillation  furnace,  which  is  still  used  extensively  in  the  district. 
Some  of  the  works  use  the  Welsh-Belgian  furnace  with  roasting  furnaces  at- 
tached thereto,  but  the  employment  of  this  type  is  not  spreading.1  In  recent 
years  there  has  been  a  tendency  to  replace  the  Silesian  furnaces  with  the 
ordinary  Belgian.  Direct  firing  has  almost  entirely  given  way  to  gas  firing, 

1  William    Blackmore,   private   communication,    August    12,    1899 ;    I   am   also   indebted  to 
Mr.  Blackmore  for  the  data  as  to  the  cost  of  coal  and  wages  of  labor  in  Wales. 


/PRESENT   ECONOMIC    CONDITIONS. 


35 


in  connection  with  which  the  tendency  has  been  lately  to  abandon  the  more 
complicated  forms  of  brick-filled  regenerative  chambers  in  favor  of  simpler 
heat-recuperative  flues,  the  common  checker-work  type  of  regenerator  be- 
coming too  rapidly  choked  by  the  escaping  zinc  fumes.1  According  to  E. 
Forbes  Carpenter,  the  British  Alkali  Inspector,  in  his  report  for  1896,  "the 
English  zinc  works  are  substituting  for  the  Belgian  furnace,  in  the  case  of 
certain  ores,  a  furnace  heated  by  producer  gas  with  two  or  three  tiers  of 
muffles.  Arrangements  have  also  been  made  in  many  English  zinc  works  to 
remove  the  fumes  of  zinc  oxide  escaping  from  the  condensers,  this  being 
done  chiefly  to  improve  the  health  of  the  workmen."  Certain  English  zinc 
works  have  begun  the  manufacture  of  sulphuric  acid  from  the  waste  fumes 
of  the  blende-roasting  furnaces. 

GREECE. — The  Kingdom  of  Greece  used  to  furnish  an  important  supply 
of  zinc  ore  to  European  smelters,  it  being  derived  entirely  from  the  mines 
of  Laurium,  but  the  output  from  that  source  has  lately  diminished  materi- 
ally. None  of  the  ore  is  smelted  in  Greece,  but  most  of  the  calamine  is 
calcined  and  the  blende  is  roasted  before  exportation.  M.  Ed.  Fuchs2  states 
that  the  cost  of  mining  zinc  ore  at  Laurium  is  4-70@7-20  fr.  per  metric  ton. 
according  to  whether  the  exploitation  is  carried  on  open  cast  or  underground 
and  at  depth,  labor  amounting  to  2-50(a5  fr.  and  powder  and  supplies  to 
2-20.  The  cost  of  production  of  sorted  ore  varies  of  course  according  to  the 
tenor  of  mineral  in  the  crude  material  mined.  A  laborer  paid  3  fr.  per  day 
is  able  to  sort  three  tons  per  day,  making  two  classes — mineral  and  waste. 
A  ton  of  mineral  sorted  from  stuff  containing  respectively  75%,  50%  and 
25 %*  will  cost: 


Francs 

Francs 

Franca 

For  mining  

8'91 

13-40 

26  '80 

For  *orting 

1'33 

2  '00 

4  '00 

Total 

10*24 

15  '40 

30*80 

In  the  first  case  1-33  tons  of  ore  must  be  mined  and  sorted  to  get  one 
ton  of  mineral ;  in  the  second,  two  tons ;  and  in  the  third,  four  tons. 

The  cost  of  calcination  is  3-80  fr.  per  ton  of  product.  Assuming  that  one 
ton  of  raw  mineral  will  yield  0-75  ton  of  calcined,  whence  one  ton  calcined 
=1-33  ton  of  raw,  the  total  cost  of  delivery  of  one  metric  ton  of  calcined 


1  Professor  W.  C.  Roberts-Austen,  in  the 
official  catalogue  of  the  British  section  at 
the  Chicago  Exposition. 


» Traite  des  Gites  Mineraux,  II,  385. 
•These    figures    refer    to   the   percentages 
of  "mineral"  in  the  crude  ore. 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


calamine  from  Laurium  ex  ship  at  Antwerp,  varying  according  to  the  per- 
centage of  mineral  in  the  crude  ore  raised  from  the  mines,  is  as  follows : 


Francs 

Francs 

Francs 

Mining  and  sorting  
Calcination  

13-40 
3'80 

20-49 
3-80 

40  96 
3-80 

Transportation  to  port  
Storage  and  loading  

7-00 
4-33 

7'00 
4-33 

7-00 
4-33 

General  expense  

1-50 

1-50 

1  50 

Transportation  to  Antwerp..  .  . 

18  'OC 

18-00 

18-00 

Total  

48-13 

55-12 

75-59 

ITALY. — The  zinc  ore  produced  on  the  Italian  mainland  is  entirely  ex- 
ported, largely  to  Swansea,  Wales,  and  to  Belgium.  Until  recently  the  im- 
portant production  of  Sardinia  has  also  been  entirely  exported,  going  chiefly 
to  Belgium,  France  and  Wales,  but  within  a  year  or  two  the  Societa  di  Mon- 
teponi  has  established  a  smelting  department  in  connection  with  its  other 
works  at  Monteponi  and  is  reducing  therein  a  small  portion  of  its  own  out- 
put of  ore.  The  fuel  employed  is  lignite. 

NETHERLANDS. — Comparatively  recently  a  somewhat  important  zinc- 
smelting  industry  has  been  established  in  the  Netherlands,  where  there  are 
three  works,  of  which  one  has  been  in  steady  operation  for  several  years.  The 
Netherlands  produce  no  zinc  ore  and  the  supply  of  the  Dutch  smelters  is 
obtained  from  foreign  countries,  being  imported  through  Eotterdam  and 
Antwerp.  The  smelteries  are  situated  in  that  portion  of  Holland  which  is 
in  close  proximity  to  Liege,  Belgium,  and  the  conditions  of  smelting  are 
quite  similar  to  those  existing  in  the  Liege  district. 

RUSSIA. — The  production  of  zinc  in  Russia  is  confined  to  the  Kingdom  of 
Poland,  where  the  industry  has  existed  since  1816.  It  is  at  present  in  a 
fair  state  of  development,  the  annual  production  of  spelter  amounting  to 
about  6,000  metric  tons.  There  are  two  works,  one  at  Bendzin,  belonging  to 
the  Sosnowice  Co.,  and  the  other  at  Dombrowa,  belonging  to  the  Derwiz- 
Szewcow-Pomeranoff  Co.  There  are  also  two  rolling  mills  in  the  King- 
dom, one  at  Sosnowice  and  the  other  at  Slawkow,  besides  a  factory  for  the 
manufacture  of  zinc  oxide.  The  ore  is  mined  in  the  neighborhood  of  the 
town  of  Olkusz  and  is  transported  by  carts  or  by  the  Ivangrod-Dombrowa 
Railway  to  the  Bendzin  and  Dombrowa  works.  The  Polish  zinc  ore  is 
identical  in  character  with  what  was  mined  in  Upper  Silesia  in  the  early 
days  of  the  zinc  industry  there;  at  present  only  calamine  is  treated.  The 
furnaces  employed  and  the  method  of  smelting  are  the  same  as  in  Upper 
Silesia.  Coal  is  obtained  from  the  Dombrowa  basin,  a  continuation  of  the 
Upper  Silesian  coal  measures. 


PKESENT   ECONOMIC    CONDITIONS.  37 

SPAIN. — The  large  output  of  zinc  ore  in  Spain  is  chiefly  exported,  by  far 
the  most  part  going  to  France  and  Belgium.  The  calamine  is  generally 
calcined  before  shipment.  A  comparatively  small  quantity  of  the  Spanish 
ore  is  smelted  by  the  Compagnie  Eoyale  Asturienne  des  Mines  at  its  works 
at  Arnao,  in  Asturias,  at  which  the  Belgian  method  of  smelting  is  employed. 
There  is  a  rolling  mill  connected  with  those  works,  in  which  a  part  of  their 
product  is  converted  into  sheet  zinc. 

The  total  production  of  zinc  ore  in  Spain  in  1899  amounted  to  119,770 
metric  tons,  of  which  the  province  of  Murcia  furnished  56,499  tons,  San- 
tander  43,825  tons,  Cordoba  6,795  tons,  Granada,  Almeria  and  G-uipuzcoa 
upward  of  2,000  tons  and  Teruel  1,520  tons.  The  exportation  of  blende  in 
1899  amounted  to  63,438  tons,  of  which  upward  of  50,000  tons  were 
despatched  to  Belgium,  6,631  tons  going  to  France  and  small  quantities  to 
Holland  and  Great  Britain.  The  exportation  of  calamine  amounted  to 
31,649  tons,  of  which  upward  of  15,000  tons  went  to  France  and  Belgium 
and  small  quantities  of  a  few  hundred  tons  to  Great  Britain  and  Holland. 
The  principal  Spanish  ports  for  the  shipment  of  zinc  ore  are  Cartagena, 
Santander,  Seville,  Almeria  and  Malaga. 

UNITED  STATES. — The  zinc-smelting  industry  of  the  United  States  is 
characterized  by  great  variations  in  practice  depending  upon  the  local  condi- 
tions of  the  different  districts.  Fortunately  all  the  zinc  ore  producing  dis- 
tricts of  the  United  States  occur  in  close  proximity  to  fuel,  which  favors 
greatly  the  metallurgical  industry,  but  the  character  of  the  fuel  as  well  as 
the  character  of  the  ore  varies  widely.  The  geological  conditions  under 
which  the  zinc  ore  of  the  United  States  is  found  are  described  in  Chapter 
IX,  to  which  reference  should  be  made. 

Eastern  Districts. — The  ore  mined  in  New  Jersey  and  Pennsylvania  is 
reduced  at  works  situated  at  Jersey  City  and  Newark,  N.  J.,  and  at  South 
Bethlehem  and  Palmerton  (near  Hazard),  Penn.,  all  of  which  are  con- 
trolled by  the  New  Jersey  Zinc  Co.  Their  production  of  spelter  is  of  much 
less  importance  than  their  production  of  zinc  oxide.  The  New  Jersey  zinc 
ore  as  mined  is  not  well  adapted  to  the  production  of  spelter,  because  of  its 
high  percentage  of  franklinite.  A  mechanical  separation  of  the  willemite 
and  franklinite  was  not  effected  in  an  entirely  successful  manner  until  the 
invention  of  the  Wetherill  magnetic  machines  (vide  Chapter  XI).  By 
means  of  those  machines  a  clean  willemite  product  is  now  obtained,  which  is 
an  excellent  ore  for  reduction  to  spelter,  furnishing  a  metal  of  exceptional 
purity.  So  far  it  has  not  been  the  policy  of  the  New  Jersey  Zinc  Co.  to  make 
a  large  production  of  spelter,  it  being  preferred  evidently  to  make  only  a 
comparatively  small  quantity,  which  can  be  sold  at  a  premium,  and  export 


38  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

the  remainder  of  its  willemite  to  European  smelters.  The  difference  be- 
tween the  market  prices  of  the  two  kinds  of  spelter  is  variable,  but  in  general 
it  is  in  the  neighborhood  of  2c.  per  Ib.  In  August,  1898,  when  prime 
Western  spelter  was  obtainable  in  New  York  at  4-5c.  per  Ib.,  the  New  Jersey 
high-grade  spelter  was  fetching  6-75c.  High-grade  spelter  is  also  produced 
by  the  Bertha  Zinc  and  Mineral  Co.  at  Pulaski,  Va. 

Both  at  Palmerton,  Penn.,  which  is  the  location  of  the  chief  works  of  the 
New  Jersey  Zinc  Co.,  and  at  Pulaski,  Va.,  the  conditions  are  favorable  to 
economical  zinc  smelting.  At  the  former  anthracite  coal  is  obtainable 
cheaply  from  the  near-by  mines.  The  Bertha  Zinc  and  Mineral  Co.  uses  for 
heating  its  furnaces  run  of  mine  coal  from  the  Pocahontas  Flat  Top  region, 
which  is  75  miles  from  Pulaski.  This  coal  assays  74-27%  fixed  carbon, 
18-79%  volatile  matter,  and  6-94%  ash.  Reduction  coal  is  obtained  from 
Altoona,  10  miles  from  Pulaski,  where  there  are  seams  of  great  thickness, 
having  a  minimum  of  20  ft.  and  a  maximum  at  one  point  of  117  ft.  This 
coal,  which  is  anthracite  in  character,  has  the  composition:  62-72%  fixed 
carbon,  10-52%  volatile  matter,  1-43%  sulphur,  and  25-33%  ash.  Labor 
is  obtainable  cheaply  at  all  the  works  in  New  Jersey,  Pennsylvania  and 
Virginia.  Refractory  material  is  obtained  from  Woodbridge,  N.  J.,  and 
Cheltenham,  St.  Louis,  Mo. 

Western  Districts. — The  most  important  producers  of  spelter  in  the 
United  States  are  situated  in  the  West,  at  various  points  where  the  general 
conditions  are  somewhat  similar.  There  are  numerous  smelteries  at  Pitts- 
burg,  Kan.,  and  vicinity,  which  enjoy  cheap  coal  and  proximity  to  the  ore 
supply,  but  are  antiquated  in  design  and  uneconomical  in  operation.1  There 
is  a  group  of  newer  works  at  Tola  and  Cherryvale,  Kan.,  which  are  a  little 
less  favorably  situated  as  to  ore  and  coal,  but  enjoy  what  is  at  present  prac- 
tically free  fuel  (natural  gas)  together  with  an  important  saving  in  labor.2 

In  the  vicinity  of  St.  Louis,  namely  at  Carondelet,  Mo.,  and  Collinsville, 
111.,  are  two  smelters  which  have  cheap  coal  (though  of  inferior  quality), 
comparatively  low  freight  on  ore  (taking  into  consideration  the  cost  of  get- 
ting the  spelter  to  market),  cheap  fire  clay  and  good  metallurgical  practice. 

The  three  groups  above  mentioned  derive  their  ore  supply  entirely  from 
the  Joplin  district,  with  the  exception  of  a  little  which  is  obtained  from 
Arkansas  and  Colorado.  The  quantity  of  ore  derived  from  Colorado  has 
lately  been  increasing  considerably,  and  this  source  of  supply  promises  soon 
to  become  an  important  factor  in  the  domestic  zinc  industry. 

1  The   smelters   at    Pittsburg,    Kan.,   were  » Largely  because   of  the   less   volume   of 

unable  to  withstand  the  competition  of  the  material — fuel  and  its  ash — which  has  to  b& 

natural-gas    smelters   and   their   works   are  handled.      The    ability   to    construct    larger 

now  idle  (1901).  furnaces  has  also  led  to  economies. 


FIG.  2. — ZINC  SMELTERY  AT  PITTSBURG,  KAN. 

The  distillation  furnaces  are  shown  at  the  left  and  the  roasting  furnaces  at  the  right  of  the  plate. 


FIG.  3. — WORKS  No.  2  OF  THE  CIIEROKEE-LANYON  SPELTER  Co., 
AT  PITTSBURG,  KAN. 


PRESENT    ECONOMIC    CONDITIONS.  39 

.  Situated  about  100  miles  southwest  of  Chicago  are  the  two  large  works 
at  Peru  and  Lasalle,  111.,  which  though  remote  from  the  Joplin  district  have 
favorable  railway  rates  from  there  and  the  additional  advantage  of  a  small 
supply  of  cheaper  ore  from  Wisconsin  and  Iowa.  Because  of  their  more 
improved  metallurgical  practice,  including  the  recovery  of  sulphuric  acid, 
and  their  undertaking  the  manufacture  of  sheet  zinc  and  acid  phosphate  of 
lime,  in  each  of  which  industries  they  realize  large  profits,  they  are  able 
to  compete  with  the  lola  smelters,  notwithstanding  the  advantage  of  the 
latter  as  to  fuel.  The  works  of  the  Empire  Zinc  Co.  at  North  Chicago, 
111.,  are  also  near  the  Wisconsin  mines.  The  Mineral  Point  Zinc  Co. 
fetches  some  ore  from  Colorado  and  New  Mexico  to  its  works  at  Mineral 
Point,  Wis.,  where  it  makes  zinc  white  and  recently  has  made  an  installation 
to  produce  sulphuric  acid  by  the  catalytic  process. 

Near  Marion,  Ind.,  there  are  three  small  works  which  have  higher  freights 
to  pay  on  Joplin  ore  than  any  of  the  other  works,  said  rates  being  not  offset 
by  the  lower  freights  on  spelter  to  Pittsburg,  Penn.,  which  is  the  most  im- 
portant consuming  district  in  the  United  States,  wherefore  those  smelters 
are  at  a  disadvantage ;  they  burn  natural  gas  but  the  supply  is  diminishing 
rapidly  and  is  no  longer  to  be  had  at  little  or  no  cost,  but  now  involves  an 
expense  of  perhaps  4@5c.  per  1,000  cu.  ft.,  which  is  equivalent  to  first- 
class  run  of  mine  coal,  such  as  Pennsylvania  bituminous,  at  $0-80 @$1  per 
2,000  Ib.  Besides  the  Joplin  ore  the  Indiana  smelters  obtain  small  supplies 
from  Wisconsin  and  Tennessee,  the  freight  rates  from  the  mines  in  the  latter 
State  being  the  same  as  from  Joplin,  Mo. 

Tardy  Development  of  Kansas-Missouri  Zinc-Smelting  Practice. — Until 
two  or  three  years  ago  the  smelters  of  Kansas  and  Western  Missouri 
employed  the  same  methods  that  were  adopted  when  the  zinc-smelting 
industry  was  first  established  there  during  the  decade  1870-1880.  A  de- 
scription of  their  conditions,  written  by  F.  L.  Clerc  in  The  Mineral  Resources 
of  the  United  States  for  1882  is  so  accurate  an  account  of  the  conditions  at 
most  of  the  works  at  Pittsburg,  Kan.,  and  vicinity  in  1900  that  it  is  here 
reproduced : 

"The  furnaces  are  built  with  the  ash-pits  above  the  ground,  with  a  sloping 
bank  of  earth  or  cinder  leading  up  to  the  furnace  floor.  The  buildings  are 
scarcely  more  than  sheds,  and  are  huddled  together  with  little  regard  to 
their  mutual  relation.  The  first  cost  of  the  buildings  is  inconsiderable. 
In  the  smelting  process  the  cheapness  of  the  fuel  renders  economy  in  this 
direction  unimportant,  and  the  cheapness  of  living  makes  labor  obtainable 
at  wages  as  low  as  anywhere  in  the  country.  The  works  are  usually  owned 
by  partners,  who  do  the  work  of  salaried  employees,  and  consider  as  profit 


40  PRODUCTION    AND   PROPERTIES    OF    ZINC. 

what  would  be  only  the  interest  on  their  money  and  their  wages  at  some 
other  occupation.  The  furnaces  roughly  constructed  of  inferior  material 
will  not  long  sustain  the  heat  required  to  exhaust  the  zinc  from  the  cinder, 
and  it  is  the  accepted  opinion  that  there  is  no  economy  in  "butchering"  the 
furnace  for  the  sake  of  a  small  additional  percentage  of  metal;  it  is  pre- 
ferred to  increase  the  production  of  the  furnace  and  to  reduce  the  cost  of 
labor  and  fuel  by  increasing  the  charge  of  ore — in  other  words  to  butcher 
the  ore  and  save  the  furnace.  At  the  same  time  the  personal  supervision  of 
the  proprietors  and  their  intimate  knowledge  of  the  business  makes  possible 
results  that  could  not  be  expected  by  a  company  operating  on  a  larger  scale." 

Since  Mr.  Clerc  wrote  as  above  there  have  been  of  course  some  improve- 
ments in  the  older  Kansas  and  Missouri  works  and  during  the  decade  1890- 
1900  most  of  them  passed  out  of  the  hands  of  individual  proprietors  into 
those  of  joint  stock  companies,  but  nevertheless  the  smelting  practice  con- 
tinued to  be  very  backward  in  many  respects.  Recently,  however,  a  radical 
change  has  taken  place  in  zinc  smelting  in  Kansas  and  because  of  the  won- 
derful natural  resources  that  have  been  taken  advantage  of  spelter  is  now 
produced  there  under  very  different  conditions  than  what  formerly  pre- 
vailed. 

Rise  of  the  Natural  Gas  Smelteries  of  Kansas. — Pittsburg,  Kan.,  owed 
its  development  to  the  productive  coal  measures  over  which  it  is  built, 
and  being  only  26  miles  from  Joplin,  with  excellent  railway  connections,  it 
became  naturally  an  advantageous  place  for  smelting  the  ore  mined  at  and 
near  Joplin.  About  1895  the  natural-gas  supply  in  the  vicinity  of  Tola, 
which  by  railway  is  approximately  100  miles  from  Joplin,  began  to  be  used 
for  zinc  smelting  and  since  then  numerous  works  have  been  erected  at  that 
point.  The  experience  has  demonstrated  that  zinc  ore  can  be  smelted  more 
cheaply  at  Tola,  under  the  conditions  which  exist  there,  than  at  Pittsburg, 
Kan.,  and  gradually  the  coal  smelteries  have  been  closed,  though  this  result 
did  not  take  place  in  a  marked  degree  until  1900.  In  1899  the  conditions  of 
the  ore  and  spelter  market  were  such  that  even  the  Tola  smelters  were  un- 
profitable. With  1900  the  unfavorable  conditions  were  ameliorated,  but  the 
increasing  competition  of  the  Tola  smelteries,  of  which  the  largest  had 
previously  been  consolidated  in  strong  hands,  prevented  the  price  of  ore  from 
falling  to  the  former  level  and  few  of  the  coal  smelters  of  Kansas  and  Mis- 
souri were  able  to  meet  the  new  scale  of  prices,  especially  under  the  further 
disadvantage  of  the  increased  price  for  coal  which  prevailed  during  1900, 
and  one  by  one  their  works  were  closed.  Thus  the  metallurgical  industry 
lost  one  of  its  most  picturesque  features,  inasmuch  as  the  irregular  groups 
of  buildings,  with  their  high-peaked  roofs  and  quaint  gables,  and  chimneys 


FIG.  4. — ZINC  SMELTERY  AT  CHEROKEE,  KAN, 


FIG.  5. — ZINC  SMELTERY  AT  NEVADA,  Mo. 

At  this  works  the  roasting  furnaces  are  constructed  on  top  of  the  distillation  furnaces, 


PRESENT    ECONOMIC    CONDITIONS.  41 

belching  flames  that  made  a  far-seen  landmark  on  the  prairie  at  night,  will 
soon  become  a  thing  of  the  past.  With  idleness  a  zinc  smeltery  rapidly  goes 
to  pieces  and  probably  the  Pittsburg  works  will  never  be  started  again  for 
any  but  spasmodic  campaigns.  In  the  ordinary  course  of  events  the  natural 
gas  at  Tola  and  elsewhere  will  be  exhausted  some  day  and  even  before  it  is 
wholly  consumed  it  will  begin  to  assume  an  expense  increasing  gradually  up 
to  the  point  where  it  will  be  more  costly  than  coal ;  upon  the  arrival  of  that 
time  Pittsburg  may  become  a  smelting  center  once  more,  but  it  will  be,  no 
doubt,  with  new  furnaces  and  new  appliances. 

Coal  Resources  of  the  United  States.* — Each  of  the  zinc-smelting  districts 
of  the  United  States  is  situated  in  close  proximity  to  a  coal  field  or  a  natural- 
gas  field,  with  the  exception  of  the  New  Jersey  works,  to  which  the  coal  has  to 
be  carried  from  the  anthracite  mines  of  eastern  Pennsylvania,  and  the  works 
at  North  Chicago,  111.,  and  Mineral  Point,  Wis.,  which  have  to  obtain  their 
supply  of  coal  from  the  northern  field  of  Illinois.  The  works  at  South 
Bethlehem,  Penn.,  and  Palmerton,  Penn.,  are  situated  in  close  proximity 
to  the  anthracite  coal  field  of  Pennsylvania.  The  Virginia  smelters  are 
located  on  the  continuation  of  the  great  Eastern  bituminous  coal  field  which 
extends  through  Pennsylvania  and  West  Virginia  to  Alabama.  The  smelters 
of  Lasalle  and  Peru,  111.,  are  in  the  northern  Illinois  coal  field,  while  those 
of  Collinsville,  111.,  and  St.  Louis,  Mo.,  draw  their  supply  from  the  southern 
Illinois  field.  Pittsburg,  Kan.,  is  located  on  the  southern  extension  of  the 
Iowa-Kansas  coal  field. 

The  anthracite  coal  mines  of  eastern  Pennsylvania  occur  in  three  districts 
known  as  the  Schuylkill,  Lehigh  and  Wyoming.  The  area  of  the  first  is  138 
square  miles,  of  the  second  38  square  miles  and  of  the  third  196  square 
miles.  There  are  15  workable  seams,  having  a  total  thickness  of  107  ft.  of 
coal,  the  thickness  of  the  measures  in  which  the  seams  are  interstratified 
being  about  3,000  ft. 

At  Lasalle  and  Peru  in  the  northern  Illinois  coal  field  there  are  three 
workable  seams  of  coal,  one  being  from  4-5  to  5  ft.  in  thickness,  another  from 
3  to  9  ft.,  averaging  6  ft.,  and  a  third  4  ft.  The  coal  from  the  uppermost 
seam  is  light,  dry  and  free-burning.  The  middle  seam  yields  a  poorer  coal. 
The  lowest  seam  is  most  highly  bituminous,  cakes  in  burning,  is  high  in 
sulphur  and  throws  off  a  heavy  soot.  In  the  Belleville  district  in  southern 
Illinois,  whence  the  Collinsville  and  St.  Louis  smelters  obtain  their  coal,  a 
seam  from  5  to  7  ft.  in  thickness  is  principally  worked.  The  Illinois  coals 
are  generally  high  in  moisture  and  often  are  very  high  in  sulphur  and  ash. 

1  This  section  refers  only  to  the  coal  resources  of  those  parts  of  the  United  States  in  which 

zinc  ores  are  smelted. 


42  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

When  burned  in  ordinary  furnaces  they  produce  great  volumes  of  black 
smoke.  The  coal  of  northern  Illinois  is  burned  successfully  in  gas  pro- 
ducers. 

Pittsburg,  Kan.,  and  the  adjacent  towns  of  Weir,  Scammon  and  Fron- 
tenac,  overlie  the  thickest  and  best  seam  of  coal  in  Kansas.  This  is  known 
as  the  Cherokee  seam.  It  extends  from  the  Indian  Territory,  entering 
Kansas  near  Chetopa,  and  runs  across  the  southeast  part  of  Labette  County, 
the  west  and  northwest  parts  of  Cherokee  and  the  southeast  part  of  Craw- 
ford, thence  entering  Missouri.  The  seam  averages  40  in.  in  thickness.  It 
is  worked  at  Scammon,  Weir,  Cherokee,  Fleming,  Frontenac,  Pittsburg, 
Arcadia  and  Minden.  The  Kansas  coal  is  high  in  ash  and  moisture  and 
throws  off  great  volumes  of  black  smoke  in  burning.  It  is  high  in  pyrite, 
wherefore  the  ash  clinkers  badly,  often  forming  a  liquid  slag  which  drips 
through  the  grate  bars.  Because  of  the  high  sulphur  content  iron  grate 
bars  are  rapidly  corroded  unless  water-cooled.  This  coal  has  not  given  suc- 
cessful results  in  gas  firing;  at  least  not  in  the  early  attempts  in  zinc 
smelting  at  Pittsburg,  Kan.,  and  Eich  Hill,  Mo.,  where,  however,  the  un- 
satisfactory results  may  have  been  due  largely  to  the  imperfection  of  the 
system  employed. 

The  anthracite  coal  of  eastern  Pennsylvania  is  in  calorific  power  one  of 
the  highest  grades  of  coal  that  is  known,  having  a  heating  value  of  14,600  to 
14,800  B.T.U.  per  Ib.  of  combustible.  The  bituminous  coal  of  northern 
and  southern  Illinois  and  Kansas  is  very  inferior  as  compared  with  the 
bituminous  coal  of  western  Pennsylvania,  Wales  and  Belgium,  having  a 
heating  value  of  only  13,500  to  14,800  B.T.U.  per  Ib.  of  combustible;  and 
being  generally  rather  high  in  ash  and  moisture,  its  relative  practical  value 
is  only  about  66%  of  that  of  the  semi-bituminous  coal  of  Pennsylvania 
which  is  taken  as  the  standard  in  the  United  States.  In  reckoning  the 
advantages  of  different  smelting  districts  it  is  highly  important  to  bear  in 
mind  the  relative  efficiency  of  the  coal  available,  since  a  good  deal  more 
work  can  be  done  with  some  kinds  than  with  others. 

The  zinc  smelters  of  northern  Illinois  employ  gas  firing  and  conse- 
quently run  of  mine  coal,  which  the  modern  practice  in  gas  firing  has  proved 
to  be  preferable  to  the  use  of  slack  and  inferior  grades  of  coal.  The  value 
of  run  of  mine  coal  at  Lasalle  and  Peru  in  1899  was  $1@$1-50  per  2,000 
Ib.  The  Matthiessen  &  Hegeler  Zinc  Co.  mines  its  own  coal.  The  smelters 
of  southern  Illinois  and  Kansas  as  a  general  thing  use  slack  coal,  which  in 
1899  cost  $0-35@$0-60  delivered  at  their  works.  In  1900  there  was  a  great 
rise  in  the  value  of  coal,  especially  in  Kansas,  where  the  same  class  which 
had  previously  been  available  at  about  $0-50  per  2,000  Ib.  delivered  could 


'PRESENT   ECONOMIC    CONDITIONS  43 

not  be  contracted  for  under  $0-75.  Run  of  mine  coal  which  in  1899  was 
worth  $1@$1-10  per  ton  at  Pittsburg,  Kan.,  in  1900  rose  to  $l-50@$l-75. 
The  common  kinds  of  southern  Illinois  coal  at  the  end  of  1900  commanded 
$1-10@$1-20  for  run  of  jiiine  delivered  at  East  St.  Louis. 

Natural-Gas  Supply. — The  competition  of  the  natural-gas  smelters  of  Tola 
and  Cherryvale,  Kan.,  has  now  rendered  zinc  smelting  with  coal-fired  fur- 
naces in  Kansas  and  Missouri  largely  a  thing  of  the  past.  The  natural  gas 
under  existing  circumstances  is  almost  a  costless  fuel,  the  smelters  being  only 
at  the  expense  of  putting  down  the  wells  and  piping  the  gas  to  their  furnaces, 
the  cost  of  maintenance  being  very  small  so  long  as  the  gas  pressure  con- 
tinues high.  Some  of  the  smelters,  however,  have  made  large  outlays  for 
acquiring  gas  lands  and  consequently  are  burdened  with  interest  charges  and 
rentals,  which  are  of  course  properly  debited  to  the  cost  of  the  gas,  but  so 
far  at  least  the  smelter  who  has  been  in  possession  of  a  10-acre  lot  with  a 
producing  gas  well  has  been  about  as  well  off  as  one  who  has  acquired  10,000 
acres  of  land,  inasmuch  as  wells  which  produce  gas  draw  directly  from  the 
subterranean  reservoirs  without  respect  to  land  divisional  lines.  As  the 
gas  flow  from  a  single  well  diminishes,  however,  the  advantage  of  having  a 
large  area  from  which  to  draw  by  means  of  other  wells  becomes  apparent, 
wherefore  the  more  prudent  smelters  have  acquired  extensive  gas  rights. 
The  rapidity  with  which  such  investments  should  be  written  off  for  re- 
demption out  of  the  profits  of  the  smelting  is  necessarily  an  extremely  un- 
certain element.  The  experience  in  Pennsylvania  and  Indiana  has  demon- 
strated that  natural  gas  becomes  more  and  more  costly  as  the  supply  is 
exhausted,  wherefore  prudence  would  indicate  that  the  resources  of  Kansas 
should  be  used  economically.  i 

The  natural-gas  field  at  lola,  Kan.,  is  comparatively  small  in  area.  Its 
length  in  an  east  and  west  line  has  been  demonstrated  by  the  drill  to  be 
about  seven  miles,  its  breadth  being  about  three  miles.  The  gas  rock  which 
lies  at  a  depth  of  800  to  1,000  ft.  below  the  surface  is  a  sandstone  of  medium- 
sized  grain,  the  stratum  having  an  average  thickness  of  20  to  25  ft.  Accord- 
ing to  Edward  Orton,  State  Geologist  of  Ohio,  who  studied  the  geological 
structure  of  the  lola  gas  field  in  1898,  its  gas-bearing  formation  is  of  the 
reservoir  type,  as  distinguished  from  the  shale-gas  type.  The  characteristics 
of  the  reservoir  type  are:  (1)  Large  flows  of  gas  from  single  wells,  volumes 
amounting  to  tens  of  millions  of  cubic  feet  per  day  being  known;  (2)  ap- 
proximately the  same  pressure  in  the  wells  tapping  the  rock,  irrespective  of 
their  widely  differing  volumes;  (3)  accompaniment  of  the  gas  by  petroleum 
with  which  is  associated  water,  usually  salt  water.  The  gas  of  these  porous 
rocks  generally  comes  to  a  sudden  end,  says  Professor  Orton,  oil  comes  in 


44  PRODUCTION  AND  PROPERTIES  OE  ZINC. 

and  fills  the  pipes  or  salt  water  shuts  off  the  gas  "like  a  light  blown  out  by 
a  gust  of  wind."  Only  by  constant  care  and  attention  in  removing  those 
substances  from  the  pipes  can  the  life  of  the  well  be  maintained,  especially  in 
its  later  stages. 

At  the  time  when  Professor  Orton  made  his  examination  upward  of  two 
dozen  wells  had  been  drilled  in  the  field,  their  production  ranging  from 
2,000,000  to  more  than  10,000,000  cu.  ft.  per  24  hours.  There  were  half 
a  dozen  of  the  number  producing  about  7,000,000  cu.  ft.  per  24  hours  apiece. 
The  rock  pressure  of  the  field  was  325  lb.,  with  an  outside  range  of  5  Ib.  in 
n  single  well.  A  little  oil  had  been  found,  mainly  on  the  western  boundary 
of  the  field  and  at  a  lower  depth  than  the  gas.  Salt  water  occurred  below 
both  gas  and  oil,  but  up  to  that  time  had  not  proved  aggressive ;  the  height 
to  which  it  rose  had  not  been  determined,  but  was  less  than  several  hundred 
feet.1 

So  long  as  the  pressure  of  a  natural-gas  supply  is  adequate  to  cause  the 
delivery  of  the  requisite  volume  of  gas,  the  only  expense  for  the  latter  is 
the  rental  of  the  land,  and  the  first  cost  of  putting  down  the  wells  and  piping 
the  gas  to  the  point  of  consumption.  As  the  pressure  diminishes,  however, 
it  becomes  necessary  to  put  down  more  wells  in  order  to  obtain  the  same 
volume  of  gas  at  the  reduced  pressure ;  more  and  longer  pipe  lines  must  be 
laid ;  and  eventually  the  wells  must  be  pumped.  Under  those  conditions  the 
gas  begins  to  assume  a  positive  cost,  which  increases  gradually  as  the  supply 
falls  off  until  the  point  is  reached  where  it  becomes  more  expensive  than  coal, 
after  which  it  can  be  considered  only  as  a  luxury  or  as  an  industrial  fuel  for 
purposes  in  which  the  cost. is  a  minor  consideration.  This  stage  in  the 
history  of  natural  gas  has  already  been  reached  in  western  Pennsylvania  and 
Indiana.  At  Pittsburgh,  Penn.,  the  cheapest  gas  furnished  in  large  quantities 
for  metallurgical  purposes  in  the  autumn  of  1899  commanded  8c.  per  1,000 
en.  ft.,  at  which  price  it  was  more  expensive  than  gas  made  artificially  from 
the  local  coal.  With  modern  gas  producers  and  run  of  mine  coal  costing 
$9-80@$0-85  per  2,000  lb.,  which  was  the  average  cost  of  coal  at  Pittsburgh 
;;t  that  time  gas  could  be  made  artificially  for  2-5c.  per  1,000  cu.  ft.  of  com- 
bustible, and  reckoning  2  cu.  ft.  of  combustible  in  that  form  as  being  equal  in 
calorific  power  to  1  cu.  ft.  of  natural  gas1  the  latter  would  have  had  to  be 
obtainable  at  5c  per  1,000  cu.  ft.  to  be  at  a  parity  in  so  far  as  actual  cost 
is  concerned.  A  coal  cost  of  $1  per  ton  would  raise  the  cost  of  the  combusti- 
ble in  producer  gas  to  2-8c.  per  1,000  cu.  ft.,  equivalent  to  natural  gas  at 

1  Reports   are   conflicting   as    to   how    the  at  least  there  appears  to  have  been  a  serious 

lola   gas    supply    is   holding   out   under   the  diminution  in  pressure. 

heavy  drain  upon  it,  especially  during  the  *  This  is  the  ratio  adopted  by  experienced 

last  three  years ;  in  some  parts  of  the  field  gas  producer  engineers  at  Pittsburg,  Penn. 


FIGS.  G  AXD  7. — WORKS  or  THE  CHEROKEE-LANYON  SPELTER  Co., 
NEAR  IOLA,  KAN. 

These  engravings  show  the  works  in  course  of  construction  (in,  1899),     Fig,  7  is  a  continuation 

of  Fig.  6  to  the  right. 


ECONOMIC    CONDITIONS.  45 

5-Gc.  The  producers?  of  natural  gas  in  Pennsylvania  and  West  Virginia 
bay  that  the  actual  cost  of  the  gas  to  them  at  points  near  the  wells  is  now 
about  5c.  per  1,000  cu.  ft.  It  has  that  cost  because  of  the  expense  of  their 
land  leases,  the  cost  of  drilling  the  wells,  the  cost  of  piping  the  gas  to  points 
of  consumption,  the  cost  of  pumping  and  the  cost  of  maintaining  the  supply 
by  means  of  new  wells  and  additional  pipe  lines  as  it  becomes  exhausted  by 
consumption.  The  drain  on  those  fields  is  so  great  that  the  expense  for 
maintenance  is  a  large  and  constantly  increasing  charge.  The  experience  in 
the  Indiana  gas  field  has  been  similar,  and  the  zinc  smelters  who  located 
there  in  1892  have  been  for  several  years  short  of  gas,  to  the  great  impedi- 
ment of  their  operations.  The  gas  which  they  now  obtain  is  said  to  cost 
them  4@5c.  per  1,000  cu.  ft.  Both  at  lola,  Kan.,  and  in  the  Indiana 
gas  field  the  original  pressure  was  greatly  inferior  to  that  which  was  regis- 
tered in  western  Pennsylvania  and  West  Virginia.  In  Indiana  the  original 
rock  pressure  was  325  lb.,  or  about  the  same  as  at  lola,  Kan.  In  1896,  after 
10  years'  drain  from  the  field,  the  rock  pressure  was  220  lb. ;  in  1897  it  was 
only  195  lb.  The  average  diminution  in  pressure  in  Indiana  in  recent  years 
has  been  20  lb.  per  annum.  The  wells  in  Indiana  cease  to  be  serviceable  at 
100  lb.  pressure. 

Besides  the  lola  field  natural  gas  has  been  found  in  Kansas  at  numerous 
isolated  points  in  a  southerly  direction  from  lola ;  Independence  and  Cherry- 
vale  being  the  extreme  southern  extensions  at  the  present  time.  There  are 
zinc  smelteries  now  in  operation  at  Cherryvale  and  at  Neodesha.  The  loca- 
tion of  these  various  gas  fields  is  shown  by  the  map  on  page  184. 

Character  of  the  Zinc  Ore  Smelted  in  the  United  States. — The  smelters  of 
New  Jersey  and  Pennsylvania  use  only  the  willemite  produced  in  New 
Jersey;  those  of  Virginia  use  only  the  calamine  mined  in  that  State,  together 
with  a  little  obtained  from  Tennessee.  The  Indiana  smelters  obtain  their 
supply  of  ore  from  Wisconsin,  Tennessee,  and  from  the  Joplin  district ;  they 
smelt  chiefly  blende.  The  large  smelters  of  northern  Illinois  derive  the  most 
of  their  ore  supply  from  the  Joplin  district,  but  get  a  considerable  quantity 
from  Wisconsin  and  a  small  quantity  from  Iowa;  they  use  chiefly  blende. 
The  smelters  of  the  St.  Louis  district  are  also  dependent  chiefly  upon  the 
Joplin  district.  The  Kansas  smelters  obtain  by  far  the  more  part  of  their 
ore  supply  from  the  Joplin  district,  using  both  blende  and  calamine,  but 
recently  have  been  getting  some  ore  from  Colorado,  which  although  of  in- 
ferior quality  to  the  Joplin  ore  has  been  found  to  give  good  results  when 
properly  mixed  and  offers  the  advantage  of  being  obtainable  at  a  much  lower 
cost  than  the  Joplin  ore.  The  great  zinc  ore  supply  of  the  Western  smelters 
is  the  Joplin  district,  where  the  chief  part  of  the  output  is  a  concentrated 


46  PRODUCTION  AMD  PROPERTIES  OF  ZINC. 

blende,  dressed  to  a  standard  of  60%  Zn  and  containing  as  a  general  thing 
less  than  2%  Fe  and  \%  Pb.  It  is  the  highest  grade  of  zinc  sulphide  ore 
produced  anywhere  in  the  world  and  because  of  its  excellence  commands 
naturally  a  high  price. 

Cost  of  Refractory  Material. — The  smelters  of  Kansas,  the  St.  Louis  dis- 
trict and  northern  Illinois  all  use  fire  clay  dug  at  Cheltenham,  a  division  of 
St.  Louis,  for  the  manufacture  of  their  retorts,  no  other  material  having 
been  found  so  well  adapted  for  that  purpose.  This  clay  costs  $1@$1-50 
f.o.b.  cars  at  the  pits.  The  freight  rate  from  St.  Louis,  Mo.,  to  Pittsburg, 
Kan.,  is  $2  per  ton,  making  the  cost  delivered  at  works  at  the  latter  place 
$3@$3-50  per  ton.  This  is  for  raw  unmilled  clay.  Chamotte,  or  cement  as 
it  is  commonly  called  in  Missouri  and  Kansas,  costs  $4@$4-50  per  ton  deliv- 
ered at  the  smelteries  in  Kansas.  The  Kansas  smelters  and  most  of  those 
in  Illinois  employ  St.  Louis  fire  brick,  of  which  the  ordinary  kind  costs  $13 
per  M.  at  St.  Louis;  a  medium  grade  is  obtainable  at  $16  per  M.,  while  the 
highest  grade  commands  $25  per  M.  The  freight  rate  on  fire  brick  from  St. 
Louis,  Mo.,  to  Pittsburg,  Kan.,  is  $2  per  ton — i.e.,  $6-50  per  M.  Fire  brick 
blocks  and  the  special  shapes  required  for  relining  furnaces  cost  $9@$10  per 
ton  at  St.  Louis,  the  freight  rate  to  Pittsburg,  Kan.,  being  also  $2  per  ton. 
The  smelters  of  New  Jersey  and  Pennsylvania  use  clay  from  Cheltenham, 
Mo.,  and  from  Woodbridge,  N.  J. 

Wages  of  Labor. — At  Pittsburg,  Kan.,  the  general  rate  of  wages  for  com- 
mon labor  is  $1-25  per  10  hours.  Cokemen  get  $1-50  and  brickmasons  $4. 
The  wages  of  smiths  and  mechanics  are  about  as  in  other  parts  of  the 
United  States.  Carpenters  receive  less,  generally  $1-50@$2.  On  the  dis- 
tillation furnaces  the  brigadiers  are  paid  $4-50@$4-70  per  double  shift  of 
24  hours;  "long  shifts"  $3-60@$3-80  per  double  shift;  "short  shifts" 
$1-30 @  1-40  per  single  shift. 

At  lola,  Kan.,  common  labor  is  paid  the  same  as  at  Pittsburg,  namely 
$1-25  per  10  hours.  For  work  on  the  distillation  furnaces,  brigadiers 
or  firemen  receive  $2-50@$2-75;  chargers,  $2-30;  metal  drawers,  $2-35; 
helpers  $1-40@$1-60,  these  rates  being  per  shift  of  12  hours  in  each  case, 
except  in  those  where  the  daily  work  is  finished  in  a  shorter  time. 

In  New  Jersey,  Pennsylvania  and  Indiana  the  furnacemen  receive  less 
than  in  the  West.  In  Indiana  chargers  are  paid  $1-90@$2-00  per  shift  of 
12  hours;  "long  shifts"  get  $1-75;  "short  shifts"  $l-25@$l-35;  metal 
drawers  $1-50 ;  ash  wheelers  and  general  laborers  $1-25, 

Centralization  of  the  American  Consumption  of  Spelter. — Although  the 
zinc-producing  industry  of  the  United  States  has  so  far  escaped  the  tend- 
ency toward  consolidation  of  interests  to  the  same  degree  which  has  been 


PRESENT    ECONOMIC    CONDITIONS.  47 

displayed  in  many  other  branches  of  American  industry,  both  the  productive 
capacity  and  the  consumptive  demand  for  spelter  have  been  centralized  in  a 
striking  manner.  Upward  of  50%-  of  the  consumption  of  spelter  in  the 
United  States  is  for  the  purpose  of  galvanizing  iron,  which  business  is  now 
chiefly  in  the  hands  of  the  constituent  companies  of  the  United  States  Steel 
Corporation.1  The  manufacture  of  sheet  zinc  is  in  the  hands  of  four 
companies.2  The  manufacture  of  brass  in  Connecticut,  which  is  the  prin- 
cipal center  of  that  industry,  is  controlled  by  one  company.  The  con- 
sumption of  spelter  for  use  in  the  desilverization  of  lead  is  also  chiefly 
in  the  hands  of  one  corporation.3  It  is  safe  to  say,  therefore,  that  75  or 
80%  of  the  demand  for  American  spelter  now  comes  from  seven  corpora- 
tions. On  the  other  hand  the  production  of  spelter  has  also  been  cen- 
tralized, practically  the  whole  of  the  active  smelting  capacity  being  now 
divided  among  seven  strong  concerns.  What  will  be  the  effect  upon  the 
American  zinc  industry  of  this  concentration  of  demand  and  supply  it  is  too 
early  to  forecast. 

1  The    United    States    Steel    Corporation       yon  Zinc  Co. ;  they  will  be  in  operation  in 
through    certain    of    its    constituent    com-       1902. 

panies  controls  the  Edgar  Zinc  Co.  and  the  3  The   United    States   Zinc   Co.,   which    is 

Girard    Smelting   Co.,    which   together   pro-  affiliated  with   the  American   Smelting  and 

duce  about  25,000  tons  of  spelter  per  annum.  Refining  Co.,   has   planned   to   build   a   zinc 

2  New    rolling    mills    have    been    built    In  smeltery  at  Pueblo,  Colo.,  during  1902. 
1901  by  the  New  Jersey  Zinc  Co.  and  Lan- 


Ill 

I 

USES  OF  ZINC  AND  ZINC  PRODUCTS. 

Zinc,  which  in  English-speaking  countries  is  commonly  known  in  trade 
under  the  name  of  spelter,  is  used  in  the  arts  for  a  great  variety  of 
puposes.  Boiled  into  sheets  it  is  employed  in  architecture  for  roofs  of 
buildings,  water  tanks,  conduits,  etc.  Alloyed  with  copper,  in  varying 
proportions,  it  forms  the  valuable  compounds,  brass  and  bronze,  while 
its  combinations  with  other  metals  find  various  uses  in  the  arts.  Iron  dipped 
into  the  molten  metal  becomes  coated  with  it  and  is  thereby  protected  against 
oxidizing  agents ;  large  quantities  of  spelter  are  used  in  this  operation,  which 
is  called  galvanizing;  it  was  first  patented  by  Crawford  in  1837.  The 
oxide  of  zinc,  produced  either  from  the  metal  or  directly  from  the  ore, 
forms  a  white  pigment  which  is  second  in  value  only  to  white  lead,  and 
is  extensively  employed.1  A  large  quantity  of  zinc  white  is  used  by  the 
rubber  trade  for  admixture  with  the  gum  in  the  preparation  of  many  articles. 
Most  of  the  zinc  produced  in  the  world  is  used  in  these  ways,  but  con- 
siderable quantities  are  consumed  in  galvanic  batteries ;  in  photo-engraving ; 
in  plates  hung  in  boilers  to  prevent  the  formation  of  scale;  for  desilveriz- 
ing lead  bullion;  for  precipitating  gold  in  the  cyanide  process;  in  the 
form  of  powder  (known  variously  as  zinc  gray,  zinc  dust,  blue  powder, 
etc.)  as  a  reducing  agent  in  organic  chemistry  (especially  the  reduction 
of  indigo  blue)  and  as  a  paint  for  iron;  and  in  the  preparation  of  numerous 
salts,  of  which  the  most  important  are  the  chloride,  employed  as  a  preserva- 
tive for  wood,  and  the  sulphate,  employed  in  medicine,  in  dyeing,  in  the 
manufacture  of  glue  and  in  the  preparation  of  a  zinc-barium  white  known  as 
lithophone. 

Itemization  of  the  Consumption  of  Spelter. — There  are  no  statistics  com- 
piled regularly  as  to  the  consumption  of  spelter  itemized  according  to  uses, 

1  Opinions  differ  as  to  the  relative  value  certain   proportion    of   barytes   is   doubtless 

of  white  lead  and  zinc  white.     Probably  a  advantageous.     In     point    of    consumption, 

mixture   of  the   two   is   better   than   either  white   lead   still   holds    the   first   place,   but 

alone,  and  in  many  cases  the  addition  of  a  zinc  white  is  gaining  rapidly. 

48 


USLS  OF  ZINC  AND  ZINC  PRODUCTS. 

except  in  a  few  of  the  countries  of  Europe,  where  the  production  of  sheet 
zinc  is  reported.  A  large  portion  of  the  production  of  spelter,  both  in  France 
and  Great  Britain  is  rolled  into  sheet.  The  Vieille  Montagne  Company, 
which  operates  works  in  France,  besides  those  in  Belgium  and  the  west  of 
Germany,  rolls  nearly  all  of  its  spelter  production,  as  will  be  seen  by 
reference  to  Chapter  IY.  W.  H.  Seamon  stated  in  the  Engineering  and 
Mining  Journal  of  October  21,  1896,  that  at  that  time  upward  of  100,000 
tons  of  zinc  sheet  were  used  annually  for  roofing  purposes  in  Europe. 
Although  there  are  no  complete  statistics  to  indicate  the  channels  of 
consumption,  there  is  no  doubt  that  a  larger  proportion  of  the  zinc  produc- 
tion of  Europe  is  employed  in  the  form  of  sheet  zinc  than  is  the  case  in  the 
United  States. 

In  1892  it  was  estimated  by  W.  H.  Seamon  that  out  of  a  total  consump- 
tion of  spelter  in  the  United  States  of  78,040  tons  of  2,000  lb.,  the 
galvanizing  trade  used  35,000;  the  brass  makers  20,500;  the  rollers  of  sheet 
zinc  15,500;  the  desilverizers  of  lead  bullion  3,500;  while  the  remaining 
3.540  tons  were  employed  for  miscellaneous  purposes.  In  1898,  according 
lo  statistics  which  I  had  occasion  to  collect,  out  of  a  total  consumption 
of  105,000  tons  the  galvanizers  used  about  55,000  tons  »(52%) ;  the 
brass  makers  24,000  (23%);  the  rollers  of  sheet  zinc  20,000  tons 
(19%);  the  lead  desilverizers  1,500  tons.  (1-5%),  and  miscellaneous 
consumers  4,500  tons  (4-5%).  In  The  Mineral  Industry,  vol.  VIII, 
it  was  estimated  that  of  the  consumption  of  spelter  in  the  United  States 
in  1899,  50%  was  used  in  galvanizing,  15%  in  brass  making,  20% 
in  the  form  of  sheet,  and  15%  for  other  purposes.  The  agreement  between 
those  figures  and  my  own  for  the  previous  year  is  very  close  with  respect 
to  the  galvanizing  and  sheet  zinc  industries.  With  respect  to  brass  and 
consumption  for  other  purposes,  I  am  disposed  to  consider  that  The  Mineral 
Industry  underestimated  the  former  and  overestimated  the  latter.1  These 
statistics  for  the  United  States,  it  should  be  noted,  do  not  take  any  account 
of  the  consumption  of  zinc  in  the  form  of  zinc  oxide  for  use  as  a  pigment 
and  other  purposes,  that  product  being  made  in  the  United  States  directly 
from  ores,  while  in  Europe  an  important  part  of  the  spelter  production  is 
consumed  in  its  manufacture. 

SHEET  ZINC. — In  Europe  the  chief  use  of  sheet  zinc  is  as  roofing  material, 
for  which  purpose  it  is  in  great  favor.  It  was  first  employed  for  roofing 

^According     to     the     statistics     of     the  of  a  total   spelter   output  of  131,546   tons. 

Eleventh    Census,    which    have    been    pub-  It  should  be  remarked,  however,   that  dur- 

lished    since    this    paragraph    was    put    in  ing  a  part  of  1899  the  production  of  sheet 

type,   the   production    of   sheet   zinc   in   the  zinc    was    considerably    restricted     by     the 

United  States  in  1809  was  17,723  tons,  out  abnormal  market  conditions. 


50  PRODUCTION    AND   PROPERTIES    OF   ZINC. 

in  1811,  when  the  Abbe  Dony,  the  founder  of  the  Belgian  zinc  industry,  in 
his  efforts  to  create  a  market  for  the  consumption  of  his  small  output  of 
spelter,  then  practically  a  new  and  unknown  metal,  roofed  a  house  with 
sheet  zinc.  During  the  same  year  portions  of  the  roof  of  the  church  of 
St.  Barthelemy  at  Liege  were  covered  with  sheet  zinc.  According  to 
W.  H.  Seamon,  both  those  roofs  were  in  good  condition  in  1896. 1  In  1820 
the  Theatre  de  la  Monnaie  at  Brussels  was  roofed  with  zinc  and  up  to  the 
time  of  its  destruction  by  fire  in  1855,  it  is  authoritatively  stated  that 
no  repairs  had  been  required.  Mosselman,  the  successor  of  Dony  and  the 
founder  of  the  Societe  Anonyme  de  la  Vieille  Montagne,  continued  the 
experiments  of  his  predecessor  with  marked  success,  and  without  any  special 
effort  on  the  part  of  the  company  many  of  the  buildings  in  Belgium, 
France  and  Germany  were  roofed  with  the  metal,  to  the  extent  that  during 
the  year  1836  it  is  said  that  upward  of  12,000  tons  of  zinc  were  used  for 
roofing  purposes  in  France,  while  the  consumption  in  England  amounted 
to  only  between,  2,000  and  3,000  tons.2  In  1867  the  zmc  producers  of 
Europe  had  careful  examinations  made  of  the  then  existing  roofs,  from  the 
observations  on  which  conclusions  as  to  the  best  method  of  laying  such 
roofs  were  deduced  and  workmen  were  trained  to  handle  the  metal  properly. 
Since  that  time  there  has  been  a  large  increase  in  the  consumption  of 
sheet  zinc  for  roofing  material  in  Europe,  where  it  is  now  recognized  as 
highly  desirable  because  of  its  great  durability  and  its  economy  as  com- 
pared with  lead  and  copper.  Its  comparatively  low  cost  has  secured  its 
application  on  structures  of  all  kinds,  including  such  buildings  as  the 
German  Imperial  Palace,  the  University  of  Bonn,  the  Berlin  Academy 
of  Fine  Arts,  the  Cathedral  of  St.  Mary  at  Duesseldorf,  Germany,  the  Hotel 
de  Ville  and  the  Cathedral  de  Sainte  Clotilde  in  Paris,  the  Haymarket 
Theater,  Canterbury  Cathedral  and  the  Government  Dock  Yards  in  England. 
In  the  United  States  previous  to  1890  it  is  said  that  there  were  only  three 
buildings  roofed  with  sheet  zinc.  Probably  the  number  of  additions  to  the 
list  between  1890  and  1900  was  small,  inasmuch  as  American  architects 
and  builders  are  still  generally  ignorant  of  the  advantages  of  the  material. 

Dimensions  and  Weight  of  Sheet  Zinc. — In  Europe  the  business  of  zinc 
roofing  is  conducted  partly  by  the  manufacturers  and  partly  by  roofing 
companies.  The  sheets  are  commonly  corrugated  and  stamped  at  the 
rolling  mills,  though  some  of  the  roofers  cut  and  stamp  their  own  sheets. 
The  usual  length  of  these  sheets  is  7  ft.  or  8  ft.,  but  sheets  10  ft.  long 
may  be  obtained  on  special  orders;  in  width  the  regular  sheets  vary  from 

%  T  Eng.  &  Min.  Jour.,  Oct.  24,  1896. 

2  Journal   of  Gas   and   Sanitary   Engineering,  1893,  p.  419. 


USES  OF  ZINC  AND  ZINC  PRODUCTS. 


51 


2  ft.  8  in.  to  3  ft.1  Sheets  of  the  following  weight  and  thickness  are 
recommended  for  roofing  purposes  by  the  Societe  Anonyme  de  la  Vieille 
Montagne,  which  company  has  had  a  very  extensive  experience  in  this 
business. 


Gauge 

THICKNESS 

Weight 
in  pounds 
per  sq.    ft. 

WEIGHT  OF  SHEETS  IN  POUNDS 

Inch 

Mm. 

33  in.  X  72  in. 

36  in.  X  84  in. 

36in.X96in 

No.  13 
No.  14 
No.  15 
No.  16 
No.  17 
No.  18 

0'029 
0-032 
0'038 
0-043 
0-048 
0-053 

0'740 
0-820 
0-950 
1-080 
1-210 
1'340 

1-088 
1-200 
1  425 
1-613 
1-800 
1-988 

17-95 
19-80 
23-51 
26'61 
29-70 
22'80 

22-85 
25-20 
29-93 
33'87 
37-80 
41-75 

26*11 
28-80     , 
34-20 
38-71 
43-20 
47-71 

Sheet  Zinc  Gauges. — The  thickness  of  metal  in  decimals  of  an  inch 
and  the  weight  in  decimals  of  a  pound  per  square  foot  by  the  conventional 
gauges  for  sheet  zinc  are  shown  in  the  following  table : 

WEIGHT  AND  THICKNESS  OF  SHEET  ZINC,  a 


AMERICAN 

BELGIAN 

VIEILLE    MONTAGNE 

Gauge 
Number 

Thickness 

Weight 

Thickness 

Weight 

Thickness 

Weight 

Decimals 

per  sq.  ft. 

Decimals 

per  sq.  ft. 

Decimals 

per  sq.ft. 

of  an  inch 

Ib. 

of  an  inch 

Ib. 

of  an  inch 

Ib. 

1 

0-002 

0-075 

O'OOIS 

0-068 

0-004 

0-150 

2 

0-004 

O'lSO 

0-0036 

0-135 

0-006 

0-225 

3 

0-006 

0-225 

0  '  0055 

0'206 

0-007 

0-263 

4 

0-008 

O'SOO 

0-0073 

0-274 

O'OOS 

0-300 

5 

O'OIO 

0-375 

G'0091 

0-341 

O'OIO 

0-375 

6 

0-012 

0-450 

O'OllO 

0-413 

O'Oll 

0-413 

7 

0-014 

0'525 

0-0128 

0'480 

-0-013 

0-488 

8 

0-016 

0-600 

0-0146 

0-548 

0-015 

0-563 

9 

0-018 

G'675 

0'0165 

0'619 

0-018 

0-675 

10 

0-020 

0-750 

0-0180 

0-675 

0-020 

0-750 

11 

0-024 

0'900 

0-0217 

0-814 

0-023 

0-863 

12 

0-028 

1-050 

0-0254 

0-953 

0-026 

0-975 

13 

0-032 

1-200 

0-0290 

1-088 

0-029 

1-088 

14 

0-036 

1-350 

0  '  0326 

1-223 

0-032 

1-200 

15 

0'040 

1-500 

0-0364 

1-365 

0'038 

1-425 

16 

0-045 

1-688 

G'0400 

1-500 

0-043 

1-613 

17 

O'OSO 

1-875 

0-0437 

1-639 

0'048 

1'800 

18 

0-055 

2  063 

0-0478 

1-793 

0-053 

1-988 

19 

0-060 

2  250 

0-0509 

1-909 

0'058 

2'175 

20 

0-070 

2  625    * 

0-0581 

2-179 

0-063 

2  363 

21 

O'OSO 

3'000 

0-0728 

2-730 

0'070 

2-625 

22 

0-090 

3-375 

0-0764 

2-865 

0'077 

2  '888 

23 

o-ioo 

3'750 

O'OSOO 

3-000 

0-084 

3-150 

24 

0'125 

4-688 

0-0896 

3-360 

0-091 

3-413 

25 

0-250 

9  375 

0  0992 

3'720 

0'098 

3'675 

26 

G'375 

14-063 

0  '  1088 

4-080 

0'105 

3-938 

27 

O'SOO 

18  "750 

28 

I'OOO 

37  '  500 

a  The  weight  of  a  cubic  foot  of  rolled  zinc  is  450  Ib.,  whence  a  sheet  1  in.  thick  should  weigh  37'5 
Ib.,  O'l  inch  3'75  Ib.,  and  O'Ol,  0'375  Ib.  per  .-q.  ft.     The  weights  in  the  above  table  have  been  com- 


puted on  that  basis. 


1  Ordinary  dimensions  of  zinc  sheets  are 
7  ft.X2  ft.  8  in. ;  7  ft.XS  ft. ;  and  8  ft.XS  ft. 
In  Europe,  sheets  of  those  dimensions  are 


made  regularly  in  all  gauges  from  No.  6  to 
No.  26,  both  inclusive :  Nos.  1  to  5  are  rolled 
only  to  order  and  of  special  dimensions. 


52  PRODI CTIOX    AND    PROPERTIES    OF    ZINC. 

The  "American*'  gauge  is  also  known  as  the  "Matthiessen  &  Hegeler"; 
it  is  used  by  the  Matthiessen  &  Hegeler  Zinc  Co.  and  the  Illinois  Zinc  Co. 
What  I  have  called  the  "Belgian"  gauge  is  taken  from  Notes  on  Building 
Construction,  by  Col.  V.  Smith.  The  figures  under  the  caption  "Vieille 
M.ontagne"  are  taken  from  a  pamphlet  distributed  by  the  Societe  Anonyme 
de  la  Vieille  Montagne  at  the  Chicago  Exposition  in  1893. 

Directions  for  Laying  Sheet  Zinc  Roofs. — As  a  general  rule  solder  should 
not  be  used  in  laying  roofs  with  sheet  zinc,  since  the  metal  is  always 
weakened  somewhat  at  the  soldered  junction,  although  perhaps  not  more 
than  other  metals  are.  The  expansion  and  contraction  of  zinc  being  greater 
than  with  other  roofing  metals,  rigid  joints  should  generally  be  avoided. 
There  is  not,  however,  any  special  difficulty  in  soldering  sheet  zinc,  except 
that  a  little  more  care  must  be  taken  in  wiping  and  smoothing  the  joints 
than  with  some  other  metals.  The  best  solder  for  this  purpose  is  com- 
posed of  33-33%  Pb  and  66-67%  Sn,  but  any  of  the  common  varieties  may 
be  used.  Soldering  flux,  known  as  "killed  spirits,"  which  is  made  by 
saturating  commercial  muriatic  (chlorhydric)  acid  with  strips  of  zinc,  is 
applied  in  the  usual  way.  The  nails  employed  in  laying  a  zinc  roof  should 
be  made  of  zinc,  but  since  such  nails  cannot  be  driven  into  hard  wood, 
galvanized  or  plain  iron  nails  are  sometimes  employed. 

Advantages  of  Zinc  Roofs. — Sheet  zinc  owes  its  value  for  roofing  purposes 
to  its  durability,  lightness  and  economy  as  compared  with  galvanized  iron, 
tin  plate,  lead,  copper,  slate  and  tile.  Galvanized  iron  being  coated  with 
zinc  should  possess  theoretically  as  much  durability  as  sheet  zinc  and 
less  weight  for  the  same  strength,  together  with  less  first  cost,  but  as  a 
matter  of  fact  the  union  of  the  zinc  and  iron  effected  in  the  process  of 
galvanizing  is  not  sufficiently  strong  to  withstand  long  the  unequal 
expansion  of  the  two  metals,  wherefore  the  zinc  coating  gradually  scales 
off,  exposing  the  iron,  and  thus  creates  an  electrical  couple,  which  results 
in  the  more  rapid  corrosion  of  the  iron  and  destruction  of  the  roof,  although 
that  may  be  delayed  somewhat  by  frequent  and  thorough  painting.  With 
the  greatest  care,  however,  15  years  is  a  long  life  for  a  roof  of  galvanized 
iron.1  The  superiority  of  sheet  zinc  over  galvanized  iron  was  shown  in 
the  case  of  the  Northwestern  Railway  station  at  Birmingham,  England, 
which  was  roofed  in  1853  with  the  latter  and  was  carefully  painted  on 
both  sides  every  three  years  and  repaired  whenever  necessary,  but  at  the 
end  of  13  years  was  found  to  be  so  rotten  that  it  had  to  be  removed;  it 
was  replaced  by  a  zinc  roof,  which  still  exists  in  perfect  condition  and  has 
given  but  little  trouble  or  expense  for  repairs.  The  coating  of  basic  zinc 

1  W.  H.  Seamon,  loc.  cit. 


USES    OF    ZINC    AND    ZINC    PRODUCTS.  53 

carbonate  which  forms  on  the  surface  of  a  zinc  roof  is  practically  insoluble 
in  atmospheric  water  and  thoroughly  protects  the  underlying  metal  from 
further  oxidation  by  atmospheric  agents.  A  zinc  roof  of  the  proper  gauge 
weighs  from  125  to  180  Ib.  per  100  sq.  ft.,  against  800  Ib.  for  lead  and 
copper,  700  to  900  Ib.  for  slate,  and  1,500  Ib.  for  tiles. 

Zinc  should  not  be  allowed  to  come  in  contact  with  iron,  copper  or  lead,, 
since  thereby  voltaic  couples  are  established,  which  destroy  the  zinc,  especially 
in  the  presence  of  moisture.  Zinc  should  not  be  laid  on  wood,  such  as- 
oak,  which  contains  acid  and  should  not  be  exposed  to  calcareous  water. 
Zinc  laid  on  flat  roofs  to  which  cats  can  gain  access  are  also  soon  corroded.1 
Another  objection  to  zinc  as  roofing  material  is  that  in  case  of  fire  it  ignites 
and  blazes  furiously  (Bloxam). 

Methods  of  Roofing  with  Sheet  Zinc. — Zinc  roofs  are  commonly  laid  in 
Europe  by  the  "roll-cap77  system,  or  as  corrugated  sheets,  or  as  shingles 
(or  tiles).  In  the  roll-cap  system,  which  is  recommended  for  slopes  of 
not  less  than  20°  and  not  more  than  36°,  the  zinc  in  sheets  of  6  to 
8  ft.  length,  usually  of  No.  13  gauge,  is  laid  upon  a  board  sheathing,  coyer- 
ing  the  rafters  in  the  usual  manner,  with  battens  laid  upon  the  sheathing 
from  comb  of  the  roof  to  eaves,  parallel  with  the  rafters  and  spaced  at 
regular  intervals  apart.  The  edges  of  the  sheets  of  zinc  are  turned  up 
for  about  1  in.  against  these  battens,  which  are  then  covered  with  a  roll 
cap  of  sheet  zinc,  making  the  union  perfectly  water-  and  weather-tight. 
Corrugated  sheet  zinc  is  used  in  the  same  manner  as  corrugated  iron, 
but  because  of  the  greater  flexibility  of  the  metal  can  be  worked  more 
easily;  on  the  other  hand  its  inferior  transverse  strength  necessitates  that 
when  the  material  is  to  be  laid  directly  on  the  roof  frame,  the  purlins  must 
be  closer  together  than  with  corrugated  iron  of  the  same  weight.  When 
corrugated  sheet  zinc  is  used  on  board  sheathing,  No.  13  gauge  is  sufficiently 
heavy,  but  when  no  sheathing  is  employed,  a  heavier  gauge  (up  to  No.  18) 
should  be  used.  Zinc  shingle  roofs  are  adapted  to  all  slopes  greater  than 
10°  and  are  considered  to  give  the  best  results  obtainable  by  the  employment 
of  zinc  for  roofing  material.  The  shingles  or  tiles  are  made  in  square, 
hexagonal  and  diamond  shapes.  When  used  on  dwelling  houses  they  are 
made  of  Xo.  13  gauge  zinc  and  a"re  usually  10-5,  13-5  or  17*5  in.  square. 
For  use  on  large  roofs  they  are  made  23-5  and  29  in.  square.  These 
shingles  are  folded  over  on  their  edges  so  as  to  engage  with  the  succeeding 
overlying  ones  of  the  next  row,  the  method  of  laying  being  the  same  as 
with  ordinary  board  shingles — i.e.,  in  rows  beginning  at  the  eaves  and  pro- 
ceeding upward  to  the  comb  of  the  roof. 

1Col.  V.  Smith,  Notes  on  Building  Construction,  vol.  Ill   (Rivingtons,  London). 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 

«k 

Cost  of  Roofing  with  Zinc. — The  Societe  Anonyme  de  la  Vieille  Montagne 
gives  the  following  data  as  to  the  roof  surface  which  can  be  covered  on  the 
average  by  an  experienced  zinc  worker,  with  a  helper,  in  a  day  of  10 
hours:  ordinary  roll-cap  system,  170@190  sq.  ft.;  ordinary  corrugated 
sheet  zinc,  210  sq.  ft.;  patent  corrugated  sheet  zinc,  190  sq.  ft.;  dia- 
mond-shaped zinc  tiles,  110  sq.  ft.;  11X11  in.  square  tiles,  130  sq.  ft.; 
133/8X13%  in.,  150  sq.  ft.;  17X17  in.,  180  sq.  ft.;  23%X33% 
in.,  190  sq.  ft.;  fish  scales,  100  sq.  ft.;  flat  roof,  sheets  divided 
from  each  other  by  sunken  gutters,  170  sq.  ft.;  wall  facing,  imitation  of 
trick,  140  sq.  ft. ;  wall  facing,  imitation  of  stone,  170  sq.  ft.  These  figures 
represent  work  on  medium-sized  surfaces,  with  the  average  number  of 
chimneys  and  other  interruptions  of  the  roofs  continuity.  On  large  roofs 
the  figures  can  be  increased  considerably  over  those  specified  above,  while 
on  roofs  with  more  than  the  average  number  of  interruptions  the  figures 
will  be  decreased. 

COST    OF    ZINC    ROOFING. 


1 

- 

!|a 

"3 

||s 

|s 

S3S 

Style  of  roofing. 

:1 

"ojs 

•fl 

•8 

Hf 

"Sw 

111! 

111! 

0>  fl 

s 

•ssra 

In  C3 

^*o  §H 

jjj 

•^"S  aSl?" 

i 

0 

* 

6 

° 

0 

* 

Ordinary  roll  cap  

36  X  96 

/No.  13 
1  No.  14 

133 
145-5 

$5-36 
6-26 

$8-37 
9-26 

$7-65 
8-37 

$12-15 
12-87 

Patent  roll  cap   .  . 

36  X  96 

fNo.  13 

138 

5-56 

8-57 

7-93 

12-43 

1  No.  14 

151 

6  "08 

9  "08 

8  '68 

13"  18 

Patent  double  ribbed   ....  a 

391  X  51* 

fNo.  13 
I  No.  14 

140-5 
155-5 

5-66 
6-27 

9-30 
9-91 

8-11 
8-86 

13-57 
14-32 

Tiles    square   .  . 

f  131X131 

No.  13 

185-5 

8-28 

10-45 

10-66 

14-06 

\  23i  X  23^ 

No.  13 

150 

6  "65 

9  "50 

8  "62 

12  '89 

Tiles    hexagonal  

10i  X  16 

No.  13 

188 

8-33 

10-65 

10-81 

14-29 

Tiles    fish-scale   . 

241 

No.  13 

151 

8-14 

12-20 

12-22 

18-39 

Ordinary  corrugated  b 
c 

29*  X  83* 
29*  X  83* 

No.  15 
No.  15 

171 
175 

7-23 
7-40 

9-84 

10-10 

10-34 
10-58 

14-25 
16-13 

a  Distance  between  pairs  of  ribs,  13  in. ;   number  of  sheets  per  square,  7-44. 
&  Iron  frame.  c  Timber  frame. 


COMPARATIVE  COST  OF  VARIOUS  ROOFS  UNDER  AMERICAN  CONDITIONS   (1896). 


Zinc. 

Tin. 

Slate. 

Galv. 
iron. 

Tiles. 

Lead. 

Copper. 

Original  cost  per  square,  includ- 
ing laying  
Repairs  in  30  years  

$11-75 
1-15 

$8-85 
11-25 

$10'5U 
3-50 

$5-75 
11-50 

$12-50 
2-50 

$21-00 

$30-00 

Interest,  6%  on  cost,  30  years.  .  .  . 

21-15 
1  '00 

16-75 
10*12 

19-90 
3"  15 

11-35 
10  "35 

22-50 
2  "25 

37-80 

54-00 

Totals 

$35  •  05 

$46-87 

$37-05 

$38-95 

$39-75 

$58-80 

$84-00 

USES    OF   ZINC    AND   ZINC    PRODUCTS.  55 

The  above  tables  are  due  to  W.  H.  Seamon,  who  computed  the  cost  of  zinc 
roofing  on  the  bases  of  value  of  $4-03  per  100  Ib.  for  sheet  zinc  in  Europe 
and  $5-75  per  100  Ib.  at  Xew  York.  In  estimating  the  cost  of  laying  zinc 
roofs  in  Xew  York,  the  European  prices  for  the  same  work  were  assumed 
as  bases  and  were  increased  by  50%. 

In  the  item  for  repairs  on  the  tin  roof,  it  was  assumed  that  it  would 
last  30  years,  provided  it  were  painted  every  two  years,  at  a  cost  of  $0-75 
per  sq.  ft.,  but  no  allowance  was  made  for  the  re-soldering  of  the  tin 
roof  which  is  occasionally  necessary,  a  similar  re-soldering  being  required  in 
the  case  of  zinc  roofs.  At  the  expiration  of  30  years  the  tin  roof  as  well  as 
the  galvanized  iron  roof  must  be  renewed;  the  slate  roof  may  possibly  be 
good  for  another  30  years,  but  the  zinc  roof  will  be  good  for  50  more  at 
least.  It  is  proper  to  take  into  consideration  also  that  sheet  zinc  has  a 
direct  value  as  old  metal  when  it  is  necessary  to  replace  it,  or  in  ease  of 
demolition  of  the  building,  which  is  not  possessed  by  tin  plate,  galvanized 
iron,  slates  or  tiling.  Another  important  advantage  over  slate  and  tile  roofs 
is  that  in  many  buildings  the  roof  framing  can  be  made  lighter. 

Employment  of  Zinc  Plates  to  Prevent  Boiler  Corrosion. — Weakening 
of  the  plates  by  corrosion  is  one  of  the  greatest  dangers  to  which  boilers 
are  liable.  Various  methods  are  used  to  prevent  it.  One  of  the  best  has 
been  found  to  be  the  suspension  of  zinc  plates  in  the  water  in  the  boiler 
by  wires  or  rods  soldered  to  the  upper  part  of  the  shell,  so  as  to  make  an 
electrical  connection.  The  zinc  plates  thus  suspended  in  the  corrosive  water 
form  with  the  steel  plates  of  the  boiler  a  galvanic  battery,  and  the  zinc  being 
gradually  consumed,  the  steel  is  protected  thereby.  In  Europe  especially 
this  is  a  favorite  method  of  preserving  steam  boilers  and  a  considerable 
quantity  of  zinc  is  consumed  in  connection  with  it.  The  manner  in  which 
the  zinc  is  employed  was  described  in  a  report  of  the  Committee  on  Boilers 
of  the  Institution  of  Mechanical  Engineers  in  1884  as  follows : 

"Of  all  the  preservative  methods  adopted  in  the  British  service,  the  use 
of  zinc  properly  distributed  and  fixed  has  been  found  the  most  effectual  in 
saving  the  iron  and  steel  surfaces  from  corrosion,  and  also  in  neutralizing  by 
its  own  deterioration  the  hurtful  influences  met  with  in  water  as  ordinarily 
supplied  to  boilers.  The  zinc  slabs  now  used  in  the  navy  boilers  are  12  in. 
long,  6  in.  wide,  and  0-5  in.  thick ;  this  size  being  found-  convenient  for 
general  application.  The  amount  of  zinc  used  in  new  boilers  at  present 
is  one  slab  of  the  above  size  for  every  20  i.  h.  p.,  or  about  1  sq.  ft.  of 
zinc-surface  to  2  sq.  ft.  of  grate-surface.  Rolled  zinc  is  found  the  most 
suitable  for  the  purpose.  To  make  the  zinc  properly  efficient  as  a  protector 


«H»  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

especial  care  must  be  taken  to  insure  perfect  metallic  contact  between  the 
slabs  and  the  stays  or  plates  to  which  they  are  attached.  The  slabs  should 
be  placed  in  such  positions  that  all  the  surfaces  in  the  boiler  shall  be  pro- 
tected. Each  slab  should  be  periodically  examined  to  see  that  its  connection 
remains  perfect,  and  to  renew  any  that  may  have  decayed ;  this  examination 
is  usually  made  at  intervals  not  exceeding  three  months.  Under  ordinary 
circumstances  of  working  these  zinc  slabs  may  be  expected  to  last  in  fit 
condition  from  60  to  90  days  immersed  in  hot  sea-water ;  but  in  new  boilers 
they  at  first  decay  more  rapidly.  The  slabs  are  generally  secured  by 
means  of  iron  straps  2  in.  wide  and  %  in.  thick,  and  long  enough  to  reach 
the  nearest  stay,  to  which  the  strap  is  firmly  attached  by  screw-bolts." 

Steam  engineers  are  not  unanimous,  however,  with  regard  to  the  efficiency 
of  zinc  as  a  preventive  of  boiler  corrosion.  Some  consider  that  zinc  is  not 
only  of  no  use,  but  may  even  be  harmful.  In  an  article  concerning  this 
subject  the  Locomotive  stated  that  in  one  case  a  tubular  boiler  had  been 
troubled  with  a  deposit  of  scale  consisting  chiefly  of  organic  matter  and 
lime.  Zinc  was  tried  as  a  preventive.  Its  beneficial  action  was  so  obvious 
that  its  continued  use  was  recommended,  with  frequent  opening  of  the 
boiler  and  cleaning  out  of  detached  scale  until  all  the  old  scale  should 
be  removed  and  the  boiler  become  clean.  Eight  or  ten  months  later  the 
water  supply  was  changed,  the  new  supply  being  supposed  to  be  free  from 
lime  and  to  contain  only  organic  matter.  After  two  or  three  months  the 
tubes  and  shell  of  the  boiler  were  found  to  be  coated  with  an  obstinately 
adhesive  scale,  composed  of  zinc  oxide  and  the  organic  matter  or  sediment 
of  the  water  used.  The  deposit  had  become  so  heavy  in  places  as  to  cause 
overheating  and  bulging  of  the  plates  over  the  fire. 

The  experience  cited  by  the  Locomotive  should  not  be  considered  as 
evidence  why  zinc  should  not  be  used  to  prevent  boiler  corrosion,  but  merely 
as  indicative  that  the  use  of  zinc  may  not  be  advisable  with  all  kinds  of 
water.  The  experience  in  Europe  and  elsewhere  has  demonstrated  the 
general  efficiency  of  zinc  for  this  purpose,  but  there  are  exceptions  to 
all  generalizations  and  the  failure  of  zinc  to  act  in  boilers  as  desired 
should  not  be  ascribed  to  inefficiency  of  the  principle,  but  on  the  contrary  to 
the  lack  of  preliminary  investigation  as  to  the  conditions  under  which  it 
was  to  be  applied. 

Consumption  of  Sheet  Zinc  in  the  Cyanide  Process  of  Gold  Extraction. — 
The  metallurgical  works  of  the  West  which  employ  the  cyanide  process  for 
extraction  of  gold  consume  a  considerable  quantity  of  sheet  zinc,  which  is 
prepared  by  the  rolling  mills  in  the  form  of  disks,  12  in.  in  diameter,  with 
a  1-in.  hole  in  the  center,  these  disks  being  made  usually  of  zinc  of  No.  9 


USES    OF    ZIXC    AND    ZINC    PRODUCTS.  ~>7 

gauge.  A  12-in.  disk  of  that  thickness  weighs  about  half  a  pound.  They 
sell  at  the  rolling  mill  for  about  2c.  per  Ib.  above  the  price  of  prime  Western 
spelter. 

The  cyanide  works  use  such  disks  for  the  preparation  of  zinc  shavings, 
turning  off  by  means  of  a  suitable  lathe  threads  or  minute  ribbons  of 
metal  approximately  0-1  mm.  in  thickness  and  0-5  mm.  in  width.  The 
method  of  preparing  such  shavings  is  described  in  detail  in  a  paper  on  the 
"Precipitation  of  Gold  from  Cyanide  Solutions"  by  myself  in  The  Mineral 
Industry,  IV,  331.  Theoretically  1  Ib.  of  zinc  should  precipitate  about 
6  Ib.  of  gold;  practically  from  5  oz.  to  1  Ib.  of  zinc  are  required  for  every 
ounce  of  gold  recovered.  Zinc  is  sometimes  employed  in  the  form  of  zinc 
dust  instead  of  shavings.  At  Deloro,  Canada,  where  zinc  dust  was  used 
the  consumption  averaged  0-54  Ib.  per  ounce  of  fine  gold  recovered  on  a 
month's  test.  The  consumption  of  zinc  in  connection  with  the  cyanide 
process  is  frequently  overestimated.  The  total  production  of  gold  by  the 
cyanide  process  in  1897  •  was  estimated  by  G.  T.  Beilby  as  follows  i1 
Africa,  825,000  oz.  of  bullion;  Australia,  308,000;  New  Zealand,  263,000; 
United  States,  190,000;  India,  18,800;  Mexico,  10,200;  other  countries, 
5,000;  total,  1,620,000,  equivalent  to  1,215,000  oz.  of  fine  gold.  Estimating 
the  zinc  consumption  at  1  Ib.  per  fine  ounce,  a  high  figure,  the  total 
requirements  in  1897  would  have  been  only  1,215,000  lb.=607-5  tons. 

Miscellaneous  Uses  of  Sheet  Zinc. — The  production  of  sheet  zinc  in 
the  United  States  is  consumed  chiefly  in  the  manufacture  of  miscellaneous 
articles,  such  as  washboards,  linings  for  refrigerators,  floor  sheets  for  stoves 
to  stand  upon,  covers  for  preserve  jars,  bath  tubs,  etc.  Special  sheets 
are  prepared  for  the  use  of  paper  and  card  makers,  who  require  them  for 
glazing  purposes.  The  American  rolling  mills  also  have  a  large  trade  in 
the  manufacture  of  plates  for  the  use  of  etchers  and  lithographers,  and 
in  the  art  of  zincography;  there  is  a  considerable  consumption  of  rods  and 
plates  of  zinc  in  connection  with  galvanic  batteries.  More  or  less  sheet 
zinc  is  used  in  the  building  trade  for  chimney  flashings,  roofing  piazzas,  etc. 

Eolled  zinc  can  be  chased,  punched  and  stamped  in  many  useful  and 
ornamental  forms  required  for  ceilings,  moldings,  friezes  and  other  archi- 
tectural purposes.  Some  sheet  zinc  is  consumed  in  lining  packing  cases  for 
valuable  and  perishable  goods ;  also  for  lining  coffins.  The  metallic  founda- 
tions for  cloth-covered  buttons  are  now  made  almost  entirely  of  stamped 
zinc.  Of  the  many  small  articles  made  of  sheet  :inc  nention  of  water  cans 
and  buckets,  sprinkling  pots,  oil  cans,  stair  treads,  *oal  Buttles  and  toys 
illustrates  the  manifold  uses  ->f  .he  uietal.  It  is  'mportant  to  note,  lowever, 

iJourn.  Soc.  Chem.  Ind.,  Feb.  28,   1898. 


58  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

that  in  many  of  these  lines  of  consumption,  where  durability  against  weather 
or  some  other  especial  requirement  is  absent,  zinc  is  not  indispensable  and 
merely  takes  the  place  of  some  other  metal,  wherefore  the  demand  for  it 
is  subject  to  a  sharp  restriction  when  the  price  of  zinc  rises  above  a  certain 
figure.  This  was  experienced  by  the  rolling  mills  in  a  striking  manner 
during  the  period  of  abnormally  high  prices  in  1899. 

ZINC  CASTINGS. — Zinc  is  well  adapted  for  ornamental  castings,  being 
capable  of  taking  very  sharp  impressions  of  the  most  delicate  lines  and 
molds,  and  small  quantities  of  the  metal  are  employed  for  that  purpose. 
Many  of  the  statuettes  and  other  ornaments  to  be  seen  in  house  furnishings 
ore  composed  entirely  of  zinc,  being  plated  subsequently  with  silver  or 
copper  under  the  designation  of  "white  bronze."  Monuments  cast  from 
spelter  are  made  to  some  extent  in  the  United  States,  a  sand  blast  being 
employed  to  give  their  surface  a  pleasing  dull  finish;  such  monuments  are 
claimed  to  be  highly  durable  and  capable  of  very  artistic  treatment,  and 
are  cheaper  than  stone  monuments. 

CONSUMPTION  OF  ZINC  IN  BRASS  MAKING. — After  the  galvanizing  and 
sheet  zinc  industries  the  manufacture  of  brass  is  the  most  important  channel 
of  consumption  for  zinc.  Brass  is  employed  chiefly  in  the  form  of  castings, 
sheets,  wire  and  tubes.  In  preparing  brass  castings  the  metal  previously 
melted  in  a  crucible  is  poured  directly  into  the  mold,  which  is  formed 
in  a  free,  fine-grained  sand  of  uniform  character  and  contained  in 
a  sectional  box  of  wood  or  cast  iron,  of  which  the  parts  are  held  together 
by  clamps.  The  uses  of  cast  brass  are  so  manifold  that  it  would 
be  futile  to  undertake  to  enumerate  all  of  them.  The  manufacture  of 
electrical  apparatus  is  a  highly  important  channel  of  consumption. 
Large  quantities  of  cast  brass  are  employed  in  naval  construction. 
Bells,  gas  fittings,  cocks  and  plumbers7  supplies,  and  many  small  ar- 
ticles required  in  architecture  and  building  call  in  the  aggregate  for  a 
large  supply  of  brass.  Sheet  brass  is.  employed  for  the  manufacture  of 
plates  intended  for  sheathing  purposes,  for  wire  drawing,  and  for  stamped 
work  and  jointed  tubing.  Many  useful  and  ornamental  articles  which 
were  formerly  produced  by  casting  are  now  more  cheaply  and  expeditiously 
made  by  stamping  out  of  sheets  of  rolled  brass.  Tubes  are  made  from  sheet 
brass  by  bending  strips  of  the  latter  to  the  proper  gauge  and  shape  and 
soldering  the  junction.  Tubes  are  also  made  by  drawing  down  short, 
thick,  cast  cylinders  of  brass  to  the  desired  gauge  and  thinness.  The 
consumption  of  brass  in  the  form  of  Muntz's  metal,  a  variety  which  contains 
a  high  percentage  of  zinc,  fell  off  largely  when  ships  ceased  to  be  sheathed,  , 
but  a  new  demand  developed  in  the  electrical  industry.  To  some  extent 


USES  OF  ZINC  AND  ZINC  PRODUCTS.  59 

ie  demand  for  brass,  and  consequently  for  the  zinc  which  is  consumed  in  its 
lanufacture,  is  governed  by  the  same  conditions  which  affect  the  demand  for 
)pper. 

In  rolling  brass  the  metal  is  melted  and  cast  into  broad  flat  molds  of 
iron,  which  are  rubbed  with  oil  and  powdered  with  charcoal  before  being 
sed.  The  ingots  for  rolling,  termed  "strips,"  are  in  the  cold  state  passed 
iccessively  between  steel  rollers  of  large  size,  which  squeeze  them  out  and 
:tend  them  lengthwise.  As  often  as  necessary  the  sheets  are  annealed 
in  a  muffle  or  reverberatory  furnace,  being  allowed  to  cool  after  each 
annealing.  After  pickling  in  acid  the  sheets  are  finished  by  passing  through 
a  set  of  highly  polished  rolls.  Muntz's  metal  can  be  rolled  hot,  wherefore 
it  is  more  cheaply  and  expeditiously  prepared  than  ordinary  sheet  brass. 

USE  OF  ZINC  FOR  DESILVERIZING  LEAD. — Zinc  plays  a  highly  important 
part  in  the  modern  metallurgy  of  lead  by  virtue  of  its  ability  to  rob  the 
latter  of  gold  and  silver,  forming  an  alloy  therewith  which  can  be  readily 
removed.  So  perfect  is  this  property  that  the  last  traces  of  both  gold  and 
silver  can  be  recovered  if  desirable,  although  in  practice  it  is  not  economical 
to  desilverize  the  lead  below  a  tenor  of  0-1  oz.  per  2,000  Ib.  Besides 
removing  the  gold  and  silver,  zinc  also  combines  with  whatever  copper  and 
tellurium  may  be  contained  in  impure  lead,  which  elements  are  not  com- 
pletely separated  by  any  process  of  "softening"  or  liquation,  and  thereby 
enables  the  production  of  purer  metal  than  is  otherwise  obtainable.  This 
property  of  zinc  finds  application  in  the  Parkes  process  of  desilverizing 
lead,  which  has  now  almost  entirely  displaced  the  older  methods  of  cupella- 
tion  and  Pattinsonizing. 

In  the  Parkes  process  a  certain  quantity  of  zinc  in  the  form  of  the 
ordinary  slabs  is  stirred  into  the  gold-  and  silver-bearing  lead  in  a  large 
iron  pot.  The  zinc  combines  with  the  gold  and  silver,  forming  a  mushy 
alloy,  which  is  removed  by  skimming,  the  lead  being  left  practically  free 
from  gold  and  silver  after  repeated  "zinkings,"  three  to  four  repetitions 
being  usually  necessary.  The  quantity  of  zinc  required  varies  according  to 
the  purity  of  the  lead  and  increases  with  the  percentage  of  silver  present. 
The  quantity  is  computed  by  Roswag1  by  the  formula : 

Z 
in  which 

Z=quantity  of  zinc  required  in  kilograms  per  metric  ton   and  Z1=quantity 
in  pounds  per  2,000  Ib. 
T=grams  of  silver  in  100  kg.  lead  and  T1=ounces  troy  of  silver  per  2,000  Ib. 

In  practice,  lead  containing  0-1%  Ag  requires  about  1-34%  Zn,  and  lead 

1  La  D6sargentation  de  Plomb,  Paris,   1884,  p.  241. 


60  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

containing  1%  Ag  requires  about  2-5%  Zn.  By  distillation  the  zinc  is 
driven  out  of  the  gold-silver  alloy,  leaving  the  gold  and  silver  behind  in  the 
retort  and  restoring  the  zinc,  minus  a  certain  loss,  for  use  again.  The  actual 
consumption  of  zinc  in  desilvering  lead  containing  1%  Ag  is  about  0*65% 
to  1%  of  the  lead  desilverized.  Although  the  production  of  lead  has  in- 
creased largely  during  the  last  10  years  the  consumption  of  zinc  for  its  desil- 
verization  has  not  increased  because  of  the  great  economy  in  the  use  of  the 
latter  which  has  been  effected  by  means  of  the  Howard  stirrer  and  press  and 
similar  devices. 

The  zinc  employed  for  the  desilverization  of  lead  should  be  low  in  iron. 
Hofman  found1  in  experimenting  with  cheap  zinc  containing  iron,  obtained 
from  galvanizing  works,  that  the  desilverization  process  was  so  retarded  and 
the  quantity  of  impure  zinc  required  was  so  great,  that  no  saving  was 
effected  by  the  use  of  the  inferior  material.  Jernegan  recorded  a  similar 
experience;2  and  Foehr  stated  that  in  using  a  spelter  which  contained  2-75% 
Pb,  0-61%  Fe,  0-077%  Cu,  and  traces  of  tin,  arsenic,  antimony,  cadmium, 
sulphur  and  carbon,  four  times  the  quantity  of  zinc  usually  required  had  to 
be  added  in  order  to  effect  a  proper  desilverization.3 

USE  OF  ZINC  IN  GALVANIZING. — The  uses  of  galvanized  iron  are  so  mani- 
fold and  well  known  that  it  is  unnecessary  to  refer  to  them  specifically  in  a 
treatise  of  this  kind.  The  subject  falls  anyway  rather  into  the  domain 
of  structural  material  than  into  that  of  the  metallurgy  of  zinc.  The  zinc 
smelter  is  interested  in  it  only  so  far  as  it  affects  the  marketing  of  his 
product.  In  general  the  zinc  consumed  in  galvanizing  is  employed  for  the 
production  of  a  protective  coating  on  iron  and  steel,  which  may  be  applied  to 
any  article  of  such  size  and  shape  that  it  can  be  dipped  into  the  galvanizing 
bath.  Another  limitation  is  that  the  article  to  be  galvanized  is  not  to  be 
•exposed  to  the  action  of  liquids  or  vapors  which  would  corrode  the  coating  of 
zinc.  Galvanizing  is  employed  probably  to  the  largest  extent  in  coating  pipes 
or  tubes  and  sheet  iron  or  steel,  plain  or  corrugated.  Galvanized  corrugated 
iron  constitutes  one  of  our  most  valuable  building  materials. 

ZINC  DUST. — A  considerable  quantity  of  zinc  is  consumed  in  the  arts  in 
the  form  of  zinc  dust,  zinc  gray,  or  indigo  auxiliary,  being  known  in  the 
trade  by  all  of  those  terms,  which  is  obtained  as  a  by-product  in  smelting. 
Zinc  dust  is  employed  chiefly  as  a  reducing  material  in  dyeing,  whence  its 
name  of  "indigo  auxiliary."  It  is  employed  to  a  less  extent  for  the  prepara- 
tion of  a  paint  for  covering  iron,  and  for  the  precipitation  of  gold  in  the 
cyanide  process  for  the  extraction  of  that  metal. 

1  Metallurgy  of  Lead,  5th  edition,  p.  430.         2  Trans.  Am.  Inst.  Min.  Eng.,  II,  288. 
3  Berg-  u.  Hfittenm.  Ztg.,  1888,  p.  28. 


USES    OF    ZINC    AND    ZINC    PRODUCTS.  61 

ZINC  WHITE. — In  Europe  a  considerable  quantity  of  spelter  is  employed 
for  the  production  of  zinc  oxide  or  zinc  white ;  in  the  United  States  that  sub- 
stance is  made  directly  from  ore.  Zinc  white  is  consumed  chiefly  as  a 
pigment,  either  alone  or  in  admixture  with  white  lead  or  barytes.  It  has 
excellent  covering  capacity  and  possesses  the  advantage  that  it  is  not  dis- 
colored by  vapors  containing  sulphureted  hydrogen,  wherefore  it  is  especially 
valuable  for  use  inside  of  such  buildings  as  are  lighted  by  ordinary 
illuminating  gas,  which  is  always  likely  to  contain  traces  of  sulphureted 
hydrogen.  Besides  being  used  as  a  pigment,  zinc  white  is  employed  exten- 
sively in  the  manufacture  of  rubber  goods. 

OTHER  USES  OF  ZINC. — Most  of  the  chemical  compounds  of  zinc  which 
are  used  in  the  arts  are  derived  from  metallic  zinc.  Of  these  zinc  sulphate 
and  zinc  chloride  are  employed  to  a  considerable  extent,  the  consumption  of 
each  amounting  to  several  thousand  tons  per  annum.  Zinc  sulphate  is  made 
in  considerable  quantity  in  Germany  directly  from  ore,  and  in  the  United 
States  to  some  extent  from  a  zinky  by-product  recovered  from  spelter  that 
has  been  used  for  the  desilverization  of  lead.  The  zinc  chloride  of  com- 
merce is  derived  entirely  from  the  treatment  of  metallic  zinc  with  chlor- 
hydric  acid. 

LIMITATION  OF  THE  USE  OF  ZINC. — Notwithstanding  the  important 
applications  which  zinc  finds  in  the  arts  it  cannot  be  considered  an  indis- 
pensable metal,  like  copper  for  example,  wherefore  its  price  is  limited ;  that 
is  to  say  if  the  price  rises  above  a  certain  figure  the  consumption  is 
immediately  restricted.  This  was  demonstrated  in  a  striking  manner  in  the 
United  States  in  1899  when  the  price  of  spelter  rose  to  7c.,  New  York,  and 
was  for  a  long  time  higher  than  5c.  At  those  figures  the  consumption  of 
spelter  was  much  restricted,  especially  in  the  sheet  zinc  and  galvanizing 
industries.  With  respect  to  the  latter  there  is  a  certain  difference  between 
the  price  of  black,  painted  corrugated  sheets  and  galvanized  sheets  at  which 
the  consumer  gives  the  preference  to  the  galvanized,  but  when  that  difference 
is  exceeded  he  will  take  the  pai.  ted  sheets  instead.  The.  difference  in  1899 
exceeded  the  parity  of  choice,  wherefore  the  demand  for  galvanized  sheets 
fell  off.  In  the  sheet-zinc  trade  a  high  price  for  zinc  leads  to  the  use  of  other 
metals  as  substitutes.  In  the  zinc-white  trade  it  increases  the  difficulty  of 
competition  with  white  lead,  if  the  price  of  the  latter  be  not  high  in  pro- 
portion, and  in  any  case  gives  headway  to  the  use  of  barytes  and  other 
inferior  substitutes.  Except  for  the  manufacture  of  brass  there  are  few 
important  uses  for  which  zinc  is  an  absolutely  indispensable  metal,  and  its 
price  is  therefore  limited  to  the  point  at  which  consumers  will  give  it  the 
choice  in  preference  to  substitutes.  With  a  price  for  spelter  of  4@5c.  per  Ib. 


62  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

at  New  York  there  ought  to  be  a  large  consumption  at  an  increasing  rate  cor- 
responding to  the  industrial  development  of  the  country.  A  price  of  5c.  per 
Ib.  or  over  cannot  be  expected  except  for  short  periods  when  there  may  be  a 
brisk  demand  and  a  shortage  in  the  supply ;  at  least  not  under  the  existing 
conditions  of  abundant  ore  supply  and  cheap  fuel.  The  average  price 
for  the  10  years,  1891-1900,  was  4-36c.  at  New  York,  according  to  the 
quotations  of  The  Mineral  Industry,  and  4-16c.  at  London,  according  to  the 
statistics  of  Henry  E.  Merton  &  Co.,  reduced  to  U.  S.  currency  at  par  of 
exchange. 


IV 

STATISTICS  OF  PRODUCTION  AND  PRICES. 

In  a  study  of  the  economic  conditions  of  the  zinc  industry  of  the  world 
an  investigation  of  the  statistics  of  production  and  consumption  and  price 
is  highly  important.  In  the  present  chapter  I  have  collected  all  the  available 
statistics  of  a  general  character,  most  of  which  are  derived  from  the  official 
sources,  partly  by  direct  reference  to  the  original  authorities,  and  partly 
from  the  compilations  of  The  Mineral  Industry,  which  are,  however/ taken 
from  the  various  official  publications  with  the  exception  of  the 
statistics  of  production  in  the  United  States,  which  are  based  upon 
direct  reports  from  the  producers.  In  making  this  acknowledgment 
to  The  Mineral  Industry  I  do  not,  however,  seek  to  thyow  off  responsibility 
for  the  accuracy  of  the  work  here  presented,  inasmuch  as  I  have  in  many 
cases  introduced  figures  which  do  not  appear  in  the  tables  of  that  publication. 
Free  use  has  also  been  made  of  the  excellent  and  highly  valuable  statistical 
compilations  of  the  Metallgesellschaft  of  Frankfurt  am  Main,  which  is  rep- 
resented in  the  United  States  by  the  American  Metal  Co.,  Ltd.,  of  New 
York.  It  is  to  be  understood,  however,  that  all  of  the  statistics  presented  in 
this  chapter  are  taken  from  the  official  publications  of  the  various  govern- 
ments unless  some  other  authority  is  specifically  referred  to.  In  a  com- 
paratively few  instances,  where  statistics  have  been  lacking  or  unavailable, 
estimates  have  been  inserted  in  order  to  permit  totals  to  be  arrived  at.  Such 
esimates  are  conventionally  indicated  by  an  asterisk. 

In  view  of  the  existence  of  so  many  different  statistical  publications,  it 
would  perhaps  have  been  advisable  to  adopt  a  particular  one  as  the  most 
authoritative  and  adhere  uniformly  to  it.  That  would  have  involved, 
however,  the  repetition  of  a  vast  amount  of  work,  besides  involving  the 
introduction  of  various  complications,  which  would  have  been  useless  in 
view  of  the  really  close  agreement  of  all  of  the  authorities.  Inasmuch  as 
each  statistician  presents  some  valuable  information  which  the  others  do 
not,  it  has  appeared  best  to  preserve  their  own  statements  in  spite  of  some 
discrepancies  (really  unimportant)  and  at  the  sacrifice  of  uniformity,  con- 
es 


64 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


sidering  that  the  use  of  any  of  their  figures  will  not  lead  to  any  material 
error.  The  zinc  industry  is  to  be  congratulated  upon  the  possession  of 
statistics  of  production,,  consumption  and  price,,  which  are  so  complete  and 
authoritative  as  to  be  of  the  highest  commercial  importance. 

PRODUCTION    OF    ZINC    ORE     IN    EUROPE     AND     AUSTRALIA. 

(In  metric  tons.) 


Year 

Algeria 

Austria 

Bel- 
gium 

France 

Ger- 
many 

Great 
Britain 

Greece 

Italy 

N.S. 
Wales 

Russia 

Spain 

Swe- 
den 

1840 
1841 
1842 
1843 
1844 
1845 
1846 
1847 
1848 
1849 
1850 
1851 
1852 
1853 
1854 
1855 
1856 
1857 
1858 
1859 
1860 
1861 
1862 
1863 
1864 
1865 
1866 
1867 
1868 
1869 
1870 
1871 
1872 
1873 
1874 
1875 
1876 
1877 
1878 
1879 
1880 
1881 
1882 
1883 
1884 
1885 
1886 
1887 
1888 
1889 
1890 
1891 
1892 
1893 
1894 
1895 
1896 
1897 
1898 
1899 
1900 

20,482 

18,380 
18,466 

:::  ;:: 

25,668 
22,689 
30,027 
42,365 
47.663 
48,582 
49.712 
69,501 
80,266 
78.345 
80,092 
79  472 

127,396 
128,743 
147,840 
150,950 
181,048 
162,383 
178  929 



5,465 
5,236 
5,916 
5.304 
5,382 

81.273 
83,274 
76,236 
75,392 
70,390 
66,141 
73,155 
74,008 
61,767 
58,066 
56,185 
54,516 
58,046 
68.699 
66,918 
57,099 
61,129 
55,537 
42,582 
43,299 
42,504 
37,713 
44,987 
45,293 
42.689 
38,805 
23,553 
20,443 
20,738 
27,606 
18,185 
19,042 
20,879 
24,537 
21,184 
15,410 
14,280 
12,260 
11,310 
11,585 
12,230 
11,630 
10,954 
11,475 
13,190 
11,715 

1,279 
3.848 
4,088 

'  8,372 
7,156 
3.120 
5,078 
11,103 
13,321 
20,702 
34,290 
47.540 
56,300 
69,236 
74,400 
80,065 
72.989 
81,346 
83,044 
85,550 
84,813 
67,059 

214,365 
226,625 
218,890 
244,363 
278,277 
303,596 
328,682 
333,598 
291,693 
313,299 
335,348 
353,149 
368,929 
369,874 
405,025 
366,780 
335,173 
419,543 
444,950 
451.222 
467  953 
533,559 
577,312 
597,193 
589,546 
632,895 
659,530 
694,711 
677,794 
632.040 
680,654 
705,177 
900,712 
677,761 
708,829 
759,437 
793,544 
800.237 
787,911 
728,616 
706.423 
729,942 
663,850 
641.706 
664,536 
639,215 

18,293 



15,807 
16,029 
7,620 
13,153 
15,310 
18,135 
12,979 
13,710 
12,990 
15.788 
13,809 
18,027 
18,847 
16.231 
17,106 
24,371 
24,000 
24,806 
25,855 
22,564 
28,006 
36,109 
33,069 
30,215 
25,982 
25,072 
23,535 
25,862 
26,841 
23,582 
22.402 
22,580 
27,311 
23,880 
22,170 
17,758 
19,629 
19,587 
23,929 
23,505 
25,071 

162 
168 
157 
265 
202 
732 
4,492 
6,443 
51,012 
80,524 
92,833 
56,426 
80,861 
79,036 
64,716 
61,968 
66,034 
88.844 
62,703 
73,411 
85,289 
72,176 
91,366 
100,574 
104.974 
107,887 
107,548 
93,143 
87,310 
97,059 
110,926 
120,685 
129,731 
132.767 
132,777 
121,197 
118,171 
122,214 
132,099 
150.629 
139,679 

24,744 
41,104 
48,124 
80,222 
70,158 
73,423 
86,822 
131,407 
113,485 
113.583 
107,380 
89,371 
101,010 
106.477 
100,174 
107,063 
70,951 
71,558 
60,980 
50.521 
42.911 
57,353 
54,193 
49,838 
49,509 
39,810 
69,012 
74,353 
71,774 
81,398 

'  74,265 
62,616 
58,964 
54.109 
64,828 
73.848 
99.836 
119.710 
86.158 

7,209 
8,518 
9,033 
14,248 
25,949 
20.841 
18,790 
23,831 
31,741 
28,146 
32,172 
33,236 
27,444 
28,198 
31,642 
35,523 
39,966 
40,795 
43,817 
43,460 
43,811 
46.255 
45,347 
44,893 
48,589 
49,571 
46,241 
49,972 
59,381 
61,843 
61,591 
54,981 
46,623 
47,029 
31,349 
44,041 
66,636 
61,627 
65,159 
61,034 

c.  '.'.'.'. 

'  43,731 

'  42  ,258 
43,405 
33,025 
33,054 
28,344 
27.695 
22,589 
20,830 
24,031 
22,700 
30,906 
32.045 
22,907 
18,505 

'.;;;;: 

16.564 
13,694 

14,642 
21,147 
25,728 
26.458 
24,002 
33,387 
19.389 
21,564 
27,340 
25,300 
28,749 
29,454 
23.598 
21,320 
21,099 
26,312 
30,096 
32,632 
28,828 
33,944 
30,531 
28,491 
25,862 
26.887 
27,463 
27,395 
36,100 
38,243 



'.'.'.'.'.'. 



97,666 



...... 

38,182 

44,125 
47,390 

8,521 
12,556 
13,091 
13,636 
21,907 
24.400 
29,703 
14,300 
17,587 
32,269 
29,800 
42,970 
30,281 

62,420 
57,213 
59,680 
54,524 

29,303 
39,561 
50,680 
20,593 

STATISTICS    OF    PRODUCTION    AND    PRICES.  65 

Besides  the  productions  reported  in  the  above  table  there  was  an  output 
in  Bosnia  of  G9  metric  tons  in  1882,  697  in  1883,  20  in  1889,  61  in  1890, 
47  in  1891,  and  16  in  1892.  Xorway  produced  300  tons  of  zinc-lead  ore 
in  1882,  200  in  1883,  571  in  1884,  300  in  1885,  1,540  in  1888,  3,278  in 
1889,  3,941  in  1890,  498  in  1891,  576  in  1892,  200  in  1894,  750  in  1896, 
908  in  1897  and  320  in  1898. 

In  comparing  the  zinc  ore  statistics  of  Europe  allowances  have  to  be 
made  for  differences  in  the  method  of  computation  employed  by  the 
statisticians  of  the  several  countries.  All  of  them  include  both  blende  and 
calamine,  but  some  report  the  production  of  raw  ore  and  some  the  produc- 
tion after  roasting  and  calcination,  which  processes  are  frequently  performed 
at  the  mines  before  shipment  of  the  ore. 

The  statistics  previous  to  1862  under  the  caption  "Germany"  represent 
only  the  production  of  Prussia;  the  output  of  the  mines  outside  of  that 
Kingdom  was  insignificant  at  that  period,  however,  and  the  statistics  for 
Prussia  from  1852  to  1862  are  practically  representative  of  the  production 
of  entire  Germany. 

There  was  a  small  production  of  zinc  ore  in  Hungary  between  1863  and 
1884,  of  which  there  are  no  statistics;  this  ore  was  smelted  at  works  in  the 
Kingdom,  producing  about  500  tons  of  spelter  per  annum  (vide  statistics  of 
spelter  production). 

The  above  table  is  deficient  in  failing  to  take  into  account  the  small  pro- 
duction of  zinc  ore  in  Turkey  and  the  considerable  production  in  Tunis1 
and  the  neutral  territory  of  Moresnet.  The  famous  mines  of  the  Vieille 
Montague  are  situated  in  the  last;  their  output  is  not  included  in  the 
statistics  of  any  official  publication. 

Many  of  the  European  countries  which  collect  statistics  of  their  zinc  ore 
production  report  them  by  provinces  and  districts,  a  valuable  system,  but 
one  that  is  rather  too  minute  for  a  general  summary  of  this  kind.  Other 
countries  report  the  production  classified  as  blende  and  calamine.  Such  a 
one  is  Belgium,  the  statistics  of  which  are  presented  in  the  subjoined  table. 
It  will  be  observed  therefrom  how  the  production  of  calamine  attained  a 
good  deal  of  importance  before  blende  was  mined  at  all,  how  subsequently 
the  production  of  blende  increased  while  that  of  calamine  diminished,  and 
how  finally  with  the  exhaustion  of  the  mines,  the  production  of  both  kinds 
dwindled  down  to  insignificant  proportions.  These  statistics  go  so  far 
back  that  they  present  a  very  interesting  record  of  the  zinc  mining  industry 
of  Belgium. 

1  Tunis  produced  4,400  tons  (1,000  kg.)  of   zinc  ore  in  1893  ;    31,000  in  1894 ;  14,800  in  1895 ; 

12.1CO  in  18%. 


66 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


PRODUCTION    OF    ZINC    ORE    IN    BELGIUM. 

(In  metric  tons.) 


Year 

Blende 

Calamine 

Total 

Year 

Blende 

Calamine 

Total 

1840 

nil 

20,482 

20,482 

1870 

15,783 

41,316 

57,099 

1841 

" 

18,380 

18,380 

1871 

19,970 

41,159 

61,129 

1842 

" 

18,466 

18,466 

1872 

20,623 

34,914 

55,537 

1843 

" 

25,668 

25,668 

1873 

13,952 

28,630 

42,582 

1844 

11 

22,689 

22,689 

1874 

17,087 

26,212 

43,299 

1845 

264 

29,763 

30,027 

1875 

18,750 

23,754 

42,504 

1846 

2,461 

39,904 

42,365 

1876 

21  ,739 

15,974 

37,713 

1847 

1,786 

45,877 

47,663 

1877 

26,310 

18,677 

44,987 

1848 

4,378 

33,204 

48,582 

1878 

27,134 

18,159 

45,293 

1849 

7,442 

42,270 

49,712 

1879 

23,229 

19,460 

42,689 

1850 

7,308 

62,193 

69,501 

1880 

23,080 

15,735 

38,815 

1851 

14,183 

66,083 

80,266 

1881 

8,169 

15,384 

23,553 

1852 

10,442 

67,903 

78,345 

1882 

2,171 

18,272 

20,443 

1853 

13,640 

66,452 

80,092 

1883 

3,814 

16,924 

20,738 

1854 

11,333 

68,139 

79,472 

1884 

12,057 

15,549 

27,606 

1855 

10,905 

70368 

81,273 

1885 

11,597 

6,588 

18.185 

1856 

11,418 

71,856 

83,274 

1886 

12,718 

6,324 

19,042 

1857 

10,487 

65,749 

76,236 

1887 

12,405 

8,474 

20,879 

1858 

19,467 

55931 

75,398 

1888 

12,370 

12,167 

24,537 

1859 

13,751 

56,639 

70,390 

1889 

10248 

10,936 

21,184 

1860 

17,284 

48,857 

66,141 

1890 

10,370 

5,040 

15,410 

1861 

17,267 

55,888 

73,155 

1891 

10,200 

4,080 

14,280 

1862 

18,884 

55,124 

74,008 

1892 

8,250 

4.010 

12,260 

1863 

14,899 

46,868 

61,767 

1893 

7,300 

4,010 

11,310 

1864 

16,309 

41,757 

58,066 

1894 

7,570 

4,015 

11,585 

1865 

14,657 

41,528 

56,185 

1895 

8,080 

4,150 

12,230 

1866 

15,734 

38,782 

54,516 

1896 

7,070 

4,560 

11,630 

•  1867 

16,594 

41,452 

58,046 

1897 

6,804 

4,150 

10,954 

1868 

16,485 

52,214 

68,699 

1898 

7,350 

4,125 

11,475 

1869 

17,334 

49,584 

66,918 

1899 

9,460 

3.730 

13,190 

There  are  few  countries  in  Europe  which  smelt  the  whole  of  their  own 
output  of  ore,  the  latter  being  shipped  naturally  to  the  most  convenient 
market,  often  in  some  other  country,  while  the  domestic  smelters  draw  their 
supplies  from  the  most  convenient  and  cheapest  sources  at  home  or  abroad. 
This  is  shown  most  strikingly  in  the  subjoined  table  of  the  exports  and 
imports  from  and  into  France,  from  which  it  appears  that  a  large  propor- 
tion of  the  French  production  of  zinc  ore  is  exported  while  the  supply  is 
made  good  by  approximately  equivalent  importations. 

FRENCH    IMPORTS    AND    EXPORTS    OF    ZINC    ORE. 

(In  metric  tons.) 


Year 

Imports 

Exports 

Year 

Imports 

Exports 

Year 

Imports 

Exports 

1892 

1895 

41,622 

61,291 

1898 

60,481 

60,664 

1893 

1896 

50.899 

62,415 

1899 

78,192 

76,104 

1894 

34,955 

58,281 

1897 

58,074 

79,909 

1900 

66,178 

54,665 

The  relative  importance  of  the  production  of  blende  and  calamine  is  also 
shown  in  the  subjoined  statement  of  the  output  of  the  mines  of  Upper 
Silesia,  which  is  the  most  important  single  zinc  producing  district  of 
Europe. 


STATISTICS    OF    PRODUCTION    AND   PRICES. 


67 


PRODUCTION  OF  THE   ZINC  MINES  AND   SMELTERIES  OF  UPPER   SILESIA,  a 

(In  metric  tons.) 


Year 

Blende 

Calamine 

Total 
zinc  ore 

Iron 
pyrites  b 

Iron 
ore  b 

Lead  ore 

Zinc 

Sheet 
zinc 

Zinc 
white, 
etc./ 

Average 
value  of 
zinc  per 
ton 

1861 

' 

283,487 

3,149 

42,033 

8,406 

968 

312 

1862 

279,722 

4,855 

41,700 

9,165 

969 

315 

1863 

234,744 

8,580 

40,600 

8  975 

1,180 

314 

1864 

237,540 

10,973 

38,573 

7,430 

833 

390 

1865 

268  384 

6  164 

35  430 

!9  164 

834 

382 

1866 

286,166 



8,767 

34,864 

6,016 

756 

392 

1867 

;;;;;;;; 

299,424 

9,912 

36,832 

5,084 

753 

389 

1868 

290,362 

11,860 

37,631 

8,084 

719 

378 

1869 

324,669 

13,123 

37,917 

11,762 

280 

382 

1870 

310,909 

16,010 

36,516 

10,047 

346 

349 

1871 

269  ,626 

14,339 

32,091 

13  452 

488 

357 

1872 



332,066 

"128 

'15,507 

14,610 

33,065 

13,854 

386 

408 

1873 

367,582 

355 

8,686 

14,589 

36,382 

13,092 

692 

478 

1874 

361,747 

1,101 

6,746 

16,866 

41,181 

16,121 

842 

423 

1875 

377,567 

1,713 

8,598 

17,871 

42,855 

15,746 

937 

45<* 

1876 

442,837 

2,253 

6,055 

19,105 

49,376 

18,612 

795 

431 

1877 

472,422 

2,074 

10,546 

19,370 

57,478 

18,699 

925 

368 

1878 

57,782 

'  432,678 

490,460 

2,891 

15,556 

20,273 

59,789 

19,031 

931 

322 

1879 

62,291 

430,041 

492,332 

3,213 

15,908 

19,064 

63,564 

19,805 

893 

300 

1880 

81,547 

445,407 

526,954 

4,028 

19,608 

17,760 

66,044 

16,732 

916 

340 

1881 

99,809 

444,281 

544,090 

2,578 

28,795 

21,078 

67,771 

24,517 

1,008 

304 

1882 

120,291 

459,056 

579,347 

2,840 

35,867 

24,230 

69,992 

20,682 

3,716 

316 

1883 

122,799 

505,185 

627,984 

2,131 

36,178 

24,810 

71,468 

24,846 

3,818 

283 

1884 

143,344 

445,985 

589,329 

1,457 

46,858 

25,861 

76,897 

25,474 

3,778 

267 

1885 

159,276 

447,330 

606,606 

1,585 

54,780 

26,313 

78,477 

25,347 

3,707 

253 

1886 

172,780 

398,490 

571,270 

2,083 

53,112 

29,286 

82,712 

25,066 

3,746 

256 

1887c 

193,826 

611,535 

805,361 

2,930 

57,559 

28.580 

82,640 

29,141 

3,128 

275 

1888 

212,264 

319,316 

531,580 

1,583 

33,344 

29,601 

84,777 

25,821 

2,811 

324 

1889 

246,955 

225,705 

572,660 

1,971 

20,268 

32,146 

86,947 

32,562 

922 

359 

1890c 

261,921 

368,495 

630,416 

1,949 

11,287 

32,498 

88,699 

32,547 

896 

440 

1891c 

271,277 

391,891 

663,168 

2,076 

8,088 

28,716 

88,420 

37,669 

1,151 

441 

1892d 

291,617 

368,230 

659,847 

2,520 

9,371 

29,049 

88,175 

33,266 

895 

386 

1893d 

287,375 

348,654 

636,029 

2,104 

7,083 

30,825 

91  ,659 

35,187 

207 

324 

1894d 

251  ,040 

323,295 

574,335 

2,874 

5,808 

33,898 

92,546 

34,518 

1,250 

284 

1895 

267,673 

273,151 

540,824 

2,316 

7,920 

31,927 

95,430 

35,676 

1,435 

270 

1896e 

275,514 

263,338 

538,852 

3,543 

7,556 

31,096 

98,323 

39,488 

1,105 

299 

1897 

270,426 

240.260 

510,686 

4,825 

12,814 

35,847 

95,547 

36,618 

1,336 

328 

1898 

289,684 

219,538 

509,222 

7,306 

11,478 

42,494 

99,011 

39,863 

1,452 

370 

1899e 

343,677 

184,637 

528,314 

5,716 

15,918 

40,828 

100,113 

35,646 

1,431 

466 

1900 

312,486 

190,304 

502,790 

6,965 

24,143 

42,098 

102,093 

38,469 

1,375 

389 

a  For  the  years  1861  to  1885,  both  inclusive,  from  Die  Bergwerks-  und  Hiittenverwaltungen  des 
Oberschlesischen  Industriebezirks,  Kattowitz,  1892;  for  1886  et  seq.  from  Statistik  des  Oberschlesischen 
Berg-  und  Hiittenmiinnischen  Vereins. 

b  The  iron  pyrites  and  iron  ore  here  reported  are  the'production  of  the  zinc  mines  and  do  not  in- 
clude the  output  of  any  of  the  Silesian  iron  mines  proper. 

c  The  statistics  for  1887, 1890  and  1891  include  252,747.  25,000  and  67,500  tons,  respectively,  of  cala- 
mine  recovered  from  the  old  dumps  of  the  Scharley  mine. 

d  The  statistics  for  1892, 1893  and  18&4  include,  respectively,  30,935,  53,586  and  39,810  tons  of  cala- 
mine  recovered  from  the  dumps  of  the  Scharley  and  Paul-Richard  mines. 

e  The  statistics  for  1896  and  1899,  respectively,  include  7,500  and  189  tons  of  calamine  from  the 
Scharley  and  Paul-Richard  dumps. 

/  Includes  zinc  white,  zinc  gray  and  residues. 

Blende  was  first  produced  in  Upper  Silesia  in  1870,  and  the  increased 
supply  of  ore  which  was  thereby  afforded  had  a  powerful  effect  upon  the 
zinc  industry  at  that  time.  The  sulphide  production  increased  rapidly,  and 
during  the  last  decade  it  became  the  more  important  source  of  zinc  in  Upper 
Silesia,  its  tenor  in  metal  being  much  higher  than  that  of  the  calamine; 


68 


PRODUCTION   AND   PROPERTIES   OF   ZINC. 


since  1895  its  tonnage  also  has  been  the  greater.  The  increasing  ratio  of 
blende  to  calamine  in  the  ore  production  of  Upper  Silesia  now  promises  to 
lead  to  some  more  important  changes  in  the  metallurgical  practice  of  that 
district,  to  which  reference  has  been  made  in  a  previous  chapter. 

The  average  value  in  marks  per  1,000  kg.  of  the  zinc  ore  product  of  Upper 
Silesia  since  1882  is  summarized  in  the  following  table : 


Year 

Calamine 

Blende 

Year 

Calamine 

Blende 

Year 

Calamine 

Blende 

1883 

5-41 

12-67 

1889 

10-43 

31-27 

1895 

5-35 

17-08 

1884 

4-43 

13-25 

1890 

11-70 

45-50 

1896 

7-80 

28-35 

1885 

3-67 

11-35 

1891 

12-41 

47-56 

1897 

8-87 

29-98 

1886 

3  '44 

11-49 

1892 

7-90 

38-68 

1898 

10-97 

41-44 

1887 

5-76 

14-72 

1893 

5-57 

21-57 

1899 

11-50 

58-47 

1888 

8'74 

24-86 

1894 

3-05 

17-52 

1900 

7-96 

40-24 

The  above  table  is  computed  on  the  basis  of  the  ore  mined,  leaving  out 
of  account  the  quantity  and  value  of  the  calamine  recovered  from  old  dumps, 
which  if  included  would  reduce  the  average  somewhat. 

GERMANY:     IMPORTS    AND    EXPORTS    OF    ZINC    ORE. 

(In  metric  tons.) 


Year 

Imports 

Exports 

Year 

Imports 

Exports 

Year 

Imports 

Exports 

1880 

19,132 

12,798 

1887 

11,232 

20.971 

1894 

14,712 

35,082 

1881 

15,461 

15,610 

1888 

8,901 

23,683 

1895 

25,818 

31,031 

1882 

24,567 

8,847 

1889 

26,812 

20,957 

1896 

21,493 

37,959 

1883 

19,651 

11,923 

1890 

38,098 

16,542 

1897 

24,735 

30,047 

1884 
1885 

17.078 
27.180 

12,217 
13,429 

1891 
1892 

37,762 
41.558 

22,123 
24,475 

1898 
1899 

48,050 
57,880 

30,408 
25,192 

1886 

19,717 

14,414 

1893 

23,883 

25,059 

1900 

68,982 

34,941 

EXPORTS    OF    ZINC    ORE    FROM    SPAIN. 

(In  metric  tons.) 


Year 

Quantity 

Year 

Quantity 

Year 

Quantity 

1871 

33,807 

1881 

^39,774 

1891 

39,581 

1872 

43,503 

1882 

38,701 

1892 

39,574 

1873 

46,562 

1883 

45,556 

1893 

30,814 

1874 

66,169 

1884 

35.580 

1894 

34,119 

1875 

42,778 

1885 

36,045 

1895 

29,360 

1876 

60,081   ' 

1886 

29,873 

1896 

36,656 

1877 

65,968 

1887 

27,253 

1897 

41,040 

1878 

37.332 

1888 

32,004 

1898 

65,573 

1879 

29,625 

1889 

36,108 

1899 

95,088 

1880 

36,414 

1890 

47,025 

1900 

a  60,970 

a  The  exportation  in  1900  is  given  as  reported  by  the  Revista  Minera,  of  Madrid.     The  figures 
for  the  previous  years  are  from  the  official  publication. 

Outside  of  Europe  itself  and  the  immediately  adjacent  colonies  in  Africa, 
the  smelters  of  Great  Britain  and  the  Continent  have  derived  but  little  ore 


STATISTICS    OF   PRODUCTION   AND   PRICES. 


69 


until  within  the  last  five  years,  when  some  important  supplies  have  been 
obtained  from  New  Jersey  and  from  Leadville,  Colo.,  and  Broken  Hill,  New 
South  Wales,  the  ore  from  the  last  two  sources  being  a  product  dressed 
from  the  mixed  sulphide  ore  which  exists  in  vast  quantity  at  each  of  those 
places.  The  exports  of  zinc  ore  from  New  South  Wales,  which  practically 
represent  the  production  of  the  Broken  Hill  mines,  are  stated  in  the  fol- 
lowing table: 

EXPORTS  OF  ZINC  ORE  FROM  NEW   SOUTH  WALES. 

(In  metric  tons.) 


Year 

1897 
1898 

Quantity 

Value 

Year 

Quantity 

Value 

29,303 
39,561 

£23,688 
28,941 

1899 
1900 

50,680 
20,593 

£49,207 
44.187 

The  production  of  spelter  by  distillation  from  this  ore  has  recently  been 
begun  in  Australia. 

PRODUCTION  OF  ZINC  ORE  IN  THE  UNITED  STATES. 

There  are  no  complete  statistics  of  the  production  of  zinc  ore  in  the 
United  States,  but  the  output  of  the  most  important  districts,  namely, 
New  Jersey  and  Kansas-Missouri,  is  reported  satisfactorily,  the 
former  by  the  New  Jersey  Geological  Survey  and  the  latter  by  the  local 
journals,  the  reports  of  which  are  summarized  regularly  by  The  Mineral  In- 
dustry. The  statistics  of  the  production  of  those  two  districts  are  presented 
in  the  following  table : 

PRODUCTION    OF    ZINC    ORE    IN    THE    MOST    IMPORTANT    DISTRICTS    OF    THE 

UNITED    STATES. 
(In  tons  of  2,000  Ib.) 


Year 

a  New  16  Kansas 
Jersey     Missouri 

Year 

a  New 
Jersey 

b  Kansas 
Missouri 

Year 

a  New 
Jersey 

6  Kansas 
Missouri 

Year 

a  New 
Jersey 

b  Kansas 
Missouri 

[1881 
1882 
1883 
1884 
1885 

55,079 
44,955 
62,814 
44,905 
43,149 

58,200 
60,300 
63,700 
74,300 
74,000 

1886 
1887 
1888 
i889 
1890 

49,142 
56,246 
51,942 
62,892 
55,572 

85,400 
98,300 
102,350 
106,750 
122,8501 

1891 
1892 
1893 
1894 
1895 

85,157 
86,574 
62,554 
66,508 
c  

145,550 
154,800 
139,770 
139,779 
144,487 

1896 
1897 
1898 
1899 
1900 

78,490 
86,210 
111,349 
194,881 
221,053 

153,082 
177,975 
235,123 
256,456 
242,500 

a  From  reports  of  the  New  Jersey  Geological  Survey.     6  As  reported  by  The  Mineral  Industry, 
c  No  statistics  were  collected  for  1895. 

The  only  statistics  of  zinc  ore  production  in  other  parts  of  the  United 
States,  which  are  available,  are  very  incomplete.  According  to  The  Mineral 
Industry,  vol.  II,  the  production  of  zinc  ore  in  Virginia  and  Tennessee  was 
8,420  tons  in  1887,  11,500  in  1888,  12,906  in  1889,  14,969  in  1890,  20,287 


70 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


in  1891,  20,295  in  1892,  and  21,000  in  1893.  According  to  recent  volumes 
of  The  Mineral  Industry  there  was  a  production  of  3,799  tons  of  blende  in 
Tennessee  in  1899  and  3,968  in  1900.  There  are  no  recent  statistics  of  the 
production  in  Virginia,  but  the  output  of  that  State  is  probably  not  more 
than  15,000  tons  per  annum,  all  of  which  is  calamine  assaying  about  40% 
Zn.  The  production  of  zinc  ore  in  Wisconsin,  chiefly  blende,  was  reported 
tc  have  been  15,000  tons  in  1900.  About  2,000  tons  per  annum  of  low 
grade  calamine  has  lately  been  produced  in  Iowa.  Small  lots  of  zinc  ore 
are  received  occasionally  from  Arkansas  and  New  Mexico.  Since  1898 
there  has  been  a  large  and  increasing  production  of  zinc  ore  in  Colorado. 
The  output  of  that  State  in  1900  was  reported  by  H.  A.  Lee,  State  Com- 
missioner of  Mines,  as  having  amounted  to  77,984  tons  of  ore,  averaging 
42%  Zn.  That  total  undoubtedly  includes,  however,  the  ore  that  was 
consumed  for  the  manufacture  of  zinc-lead  pigment  at  Canon  City,  Colo., 
and  for  the  manufacture  of  zinc  white  at  Mineral  Point,  Wis.1  During 
1901  the  Leadville  mills  produced  23,261  tons  of  zinc  ore,  of  which  about 
80%  was  exported.  The  Leadville  product  averages  approximately  45% 
Zn,  6%  Pb  and  12%  Fe.  Some  which  is  concentrated  at  Denver  from 
the  same  kind  of  crude  ore,  by  means  of  the  Wetherill  magnetic  machines, 
averages  50%  Zn,  1%  Pb  and  10%  Fe.  Besides  from  Leadville  there  are 
also  shipments  of  zinc  ore  from  Eico,  Kokomo,  Silver  Plume,  Montezuma, 
Creede  and  elsewhere  in  Colorado.  The  ore  shipped  from  Creede  averages 
about  56%  Zn,  5%  Pb  and  1%  Fe. 

EXPORTS    OF    ZINC    ORE    FROM    THE    UNITED    STATES. 


Year 

Short  Tons 

Total  Value 

Value  per  Ton 

Metric  Tons 

1897 
1898 
1899 
1900 

9,251 
11,782 
28,221 
40561 

211,350 
299,870 
725,944 
1,133,663 

$22-85 
25-54 
25-72 
27-95 

8,391 
10,686 
25,602 
36,796 

There  were  occasional  exports  of  zinc  ore  from  the  United  States  previous  to  1897,  but  they 
were  not  reported  separately  in  the  official  statistics      The  quantity  was  not  large  in  any  year. 

Of  the  exportation  of  ore  reported  in  the  above  table,  7,040  tons  ($213,- 
205)  in  1899  and  12,794  tons  ($373,528)  in  1900  were  despatched  through 
the  ports  of  Galveston,  Tex.,  and  New  Orleans,  La.,  the  remainder  going  out 
chiefly  via  New  York  and  Philadelphia.  The  exports  through  New  York 
and  Philadelphia  are  of  New  Jersey  willemite;  those  from  Galveston  and 
New  Orleans  are  chiefly  of  Colorado  ore,  but  include  occasional  lots  from 
the  Joplin  district. 

1  It  appears  as  if  there  might  be  a  mistake  in  the  figures  reported  for  Colorado  in   1900. 


STATISTICS   OF   PRODUCTION    AND   PRICES. 


71 


WORLD'S   PRODUCTION  OF  ZINC. 

(In  metric  tons.) 


Year 

Austria 

Belgium 

France 

Germany 

Great 
Britain 

Nether- 
lands 

Russia 

Spain 

United 
States 

Total 

1845 
1846 

388 
413 

7,221 
8  963 

17,100 
22  260 



3,569 







1847 

352 

10241 

22400 

1848 

1  395 

10,850 

20,190 

1,000 

4,000 

1849 

13,579 

26,270 

1850 

14808 

28  670 

2.606 

1851 

15  250 

30  620 

1852 

16,672 

34,721 

1853 

18,817 

34  673 

1854 

*  1,500 

19,553 

36873 

*  1,000 

1855 

20,633 

38,254 

1,107 

1856 

866 

22  900 

38  326 

a  71  000 

1857 

1,055 

24526 

43,611 

a  79000 

1858 

1,580 

34  191 

52  777 

3,522 

1859 

1,246 

28,631 

49,282 

3,757 

1860 

1,301 

22  027 

55  346 

4.428 

1  838 

1861 

28  150 

58  573 

4  487 

1862 

25  861 

59,767 

2,186 

a  100  000 

1863 

28  978 

60  315 

3897 

1864 

30,718 

59,248 

4,106 

1865 

34  244 

56  490 

4,533 

3  089 

1866 

34,659 

60,221 

3,244 

1867 

38  684 

63,874 

3  811 

ollO  000 

1868 

44  347 

66  132 

3  774 

1869 

1,866 

47  407 

69  851 

4,573 

1870 

1,908 

45,754 

63980 

4,000 

3,780 

a  130  000 

1871 

45  623 

58,297 

5,047 

3  166 

1872 

41,838 

58,386 

5,276 

2940 

1873 
1874 

2.285 
2,818 

42.314 
46,088 

12,627 
12,783 

62,755 
70,426 

4.544 
4,543 

3,378 
4,128 

2,993 
3,295 

6664 
9074 

137,560 
153,155 

1875 
1876 

1877 

2,940 
3,979 
4,519 

49,960 
47,981 
55,923 

13,739 
*  14,  000 
*  15,  000 

74,337 
83.227 
94,996 

6,823 
6,750 
6,384 

3,988 
4,626 
4635 

3,831 
4.349 
3,780 

13,914 
14,520 
15,281 

169,532 
179,432 
200,518 

1878 

3623 

61,227 

*  16,  000 

94  953 

6,412 

3,646 

3  775 

17  242 

206  878 

1879 

1880 
1881 
1882 

3,280 
3,756 
4,119 
4,791 

57,157 
59,880 
69,800 
72,947 

*  17,  000 
*18.000 
18,509 
18,525 

96,756 
99,646 
105.478 
113.418 

5,645 
7,279 
23,660 
26,501 

4,321 
4.390 
4,542 
4  462 

3,800 
4,221 
7,032 
7  310 

19,057 
21  ,080 
27,225 
30642 

207,016 
218,252 
260,365 
278,596 

1883 

4,539 

75,366 

15,915 

116854 

29,630 

3809 

6.843 

33,375 

286,331 

1884 

4,536 

77,487 

16,884 

125,276 

30,238 

4.313 

4  295 

35.585 

298,614 

1885 

3,948 

80.298 

15,108 

129  098 

24,690 

4  579 

4  247 

36,921 

298,889 

1886 
1887 
1888 
1889 

3,843 
3,609 
4,001 
4,840 

79,246 
80,468 
80,675 
82,526 

16.132 
16,712 
16,960 
17,982 

130,854 
130,444 
133,224 
135  974 

21,572 
20,228 
27,214 
31,302 

:::::::: 

4,190 
3,621 
3,869 
3.681 

4,327 
5,349 
5,117 
5  640 

-38,696 
45,682 
50,731 
53,414 

298  860 
306,113 
321,791 
335,359 

1890 
1891 
1892 
1893 
1894 
1895 
1896 
1897 
1898 
1899 
1900 

5,449 
5,006 
5,237 
5,870 
6,810 
6.456 
6,888 
6,236 
7,302 
7,192 
6,742 

82,701 
85,999 
91.546 
95,665 
97,041 
107,664 
113,361 
116.067 
119,067 
122,843 
119,317 

19,372 
20,596 
20,680 
22.419 
23,387 
24,200 
35,585 
38,067 
37,155 
39,274 
36,325 

139.266 
139,353 
139.938 
142,956 
143,577 
150.286 
153,082 
150,739 
154,867 
153,155 
155,790 

29,614 
29,883 
30,798 
28,829 
32.578 
29,967 
25,278 
23,805 
28,387 
32,222 
30,309 

*2,743 
*3565 
4,266 
4,847 
6,706 
6.808 
6,335 
*6,500 

3,768 
3,675 
4369 
4,522 
5,014 
5,029 
6257 
5.868 
5,664 
6325 
5,970 

5,919 
5,656 
5.925 
5,752 
5,100 
5,845 
6,133 
6.244 
6,031 
6,184 
5,785 

61,111 
72,836 
76,279 
69,159 
67,135 
79,462 
74.280 
91  .070 
103,514 
117.644 
111,794 

347,200 
363,004 
374,772 
377,915 
384,207 
413,175 
425,711 
444,802 
468,795 
491,174 
478,532 

*  Estimated,     a  According  to  F.  Laur,  Bull,  de  la  Soc.  de  1'Ind.  Minerale,  1874,  p.  395    et  seq. 

The  consumption  of  spelter  in  Europe  did  not  attain  much  consequence 
previous  to  1840.  The  statistics  of  production  previous  to  1845  are  rery 
incomplete.  Germany  produced  10,000  tons  of  spelter  in  1838,  10,980  in 
1840  and  18,000  in  1843.  Austria  produced  105  tons  in  1840,  and  Russia 
made  2,739  tons  in  the  same  year.  In  1846  the  production  of  zinc  in 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


Europe  amounted  to  40,000  tons,  rising  to  50,000  tons  in  1850  and  62,000 
tons  in  1853.  In  1901  the  world's  production  of  spelter  in  tons  of  2,240  lb., 
according  to  Henry  E.  Merton  &  Co.,  was  as  follows,  the  figures  in  brackets 
being  the  corresponding  ones  for  1900 :  Belgium,  Holland,  Ehenish  Prus- 
sia and  Westphalia,  199,285  (186,320);  Silesia,  106,385  (100,705);  Great 
Britain,  29,190  (29,830) ;  France  and  Spain,  27,265  (30,620) ;  Austria  and 
Italy,  7,700  (6,975) ;  Poland,  5,935  (5,875) ;  United  States  122,830  (110,- 
465)  ;  total,  498,590  (470,790). 

The  above  table  of  spelter  production  of  the  world  does  not  include  the 
zinc  contents  of  white  vitriol  made  directly  from  ore  in  Germany;  nor 
of  zinc  white  made  directly  from  ore  in  the  United  States.  It  does  not 
include,  moreover,  the  zinc  gray  (zinc  dust)  recovered  as  a  by-product  and 
marketed  in  that  form  by  the  smelters  of  Upper  Silesia,  and  presumably 
does  not  include  such  of  the  same  product  as  is  marketed  by  the  smelters  of 
Ehenish  Prussia,  Westphalia  and  Belgium.  The  statistics  of  spelter  pro- 
duction are  transcribed  from  the  official  reports  of  the  respective  countries 
with  the  exceptions  noted  below,  in  connection  with  which  some  additional 
information  is  presented. 

United  States. — The  statistics  used  are  those  of  The  Mineral  Industry 
except  for  the  years  1895  and  1896,  for  which  the  statistics  of  the  American 
Metal  Co.  are  adopted,  the  figures  of  The  Mineral  Industry  for  those  years 
being  probably  incorrect.  There  is  also  ground  for  suspicion  as  to  The 
Mineral  Industry  figures  for  1892  and  1893,  but  they  have  been  permitted  to 
stand,  the  errors  (if  they  exist)  being  less  important  than  those  for  1895 
and  1896. 

Great  Britain. — Statistics  for  Great  Britain  subsequent  to  1880  have  been 
computed  from  the  reports  of  Henry  E.  Merton  &  Co.  of  London,  the 
British  bluebooks  giving  only  the  quantity  of  zinc  estimated  as  obtainable  in 
smelting  the  ore  produced  in  the  United  Kingdom.  The  inclusion  of 
the  metal  derived  from  foreign  ores  explains  the  apparently  great  increase 
in  the  British  production  from  1880  to  1881.  The  spelter  product  of  ore 
mined  in  the  United  Kingdom  is  reported  by  the  British  Government  for 
the  years  subsequent  to  1880  as  follows : 


Year 

Tons 

Year 

Tons 

Year 

Tons 

Year 

Tons 

1881 

15,192 

1886 

9.036 

1891 

9,037 

1896 

7,224 

1882 

16,344 

1887 

9,920 

1892 

9,496 

1897 

7,162 

1883 

13,826 

1888 

10,166 

1893 

9.585 

1898 

8,711 

1884 

10,081 

1889 

9,546 

1894 

8,260 

1899 

8,837 

1885 

9,938 

1890 

8,692 

1895 

6,760 

1900 

9,211 

STATISTICS    OF    I'llODfCTlOX    AND   P1JICES. 


73 


Germany. — Previous  to  1862  the  production  of  Germany  is  assumed  as 
identical  with  the  production  of  Prussia  as  reported  in  the  statistics  for  that 
Kingdom.  By  far  the  larger  part  of  the  spelter  production  of  Germany 
is  due  to  the  works  of  Upper  Silesia,  the  output  of  which  has  been  stated 
in  a  previous  table.  Practically  the  entire  remainder  of  the  German  pro- 
duction is  made  in  Ehenish  Prussia  and  Westphalia.  The  German  output 
of  spelter  in  1901  was  166,283  tons. 

Hungary. — Hungary  produced  spelter  between  1863  and  1884  as  follows: 


Year 

Tons 

Year 

Tons 

Year 

Tons 

Year 

Tons 

Year 

Tons 

1864 

116 

1868 

323 

1872 

557 

1876 

567 

1880 

554 

1865 

204 

1869 

458 

1873 

616 

1877 

66 

1881 

612 

1866 

375 

1870 

415 

1874 

622 

1*78 

418 

1882 

605 

1867 

348 

1871 

463 

1875 

513 

1879 

13 

1883 

205 

Netherlands. — The  production  of  spelter  in  Holland  has  been  computed 
from  Merton's  reports,  there  being  no  official  statistics  for  that  Kingdom. 

Italy. — A  small  production  of  spelter  in  1900  has  not  been  included. 

Russia. — The  production  in  1899  and  1900  is  entered  as  reported  by 
Henry  R.  Merton  &  Co.,  the  official  statistics  for  those  years  not  having  been 
published  yet.  The  entire  production  of  zinc  in  Russia  is  derived  from 
the  Kingdom  of  Poland,  where  there  are  only  two  producers,  the  reports 
for  which  by  the  Messrs.  Merton  are  always  practically  the*  same  as  the 
official  figures. 

Comparison  of  Statistics  of  Production. 

The  statistics  of  total  zinc  production  of  the  world  compiled  in  the  above 
table  compare  with  those  of  Henry  R.  Merton  &  Co.,  which  are  adopted  by 
the  Metallgesellschaft,  as  follows : 


Year 

Official 

Merton 

Year 

Official 

Merton 

1881 

260  365 

1891 

363.004 

362.204 

1882 

278'596 

1892 

374,772 

372.900 

1883 

286  331 

'    '285,036" 

1893 

377,915 

378.093 

1884 

298,614 

299,420 

1894 

384.207 

380,877 

1885 

298  889 

300  200 

1895 

413,175 

416,621 

1886 

298  860 

298604 

1896 

425.711 

424,141 

1887 

306  1  13 

307.020 

1897 

444,802 

443,302 

1888 

321  791 

323.397 

1898 

468,795 

469,031 

1889 

335.359 

335,450 

1899 

491,331 

490,205 

1890 

347  200 

348,585 

1900 

478.532 

478,323 

The  agreement  of  the  above  compilations  is  sufficiently  close  to  pass 
without  comment.  It  is  very  complimentary  to  the  statisticians  of  Henry 
R.  Merton  &  Co.  and  the  American  Metal  Co.,  who  make  a  practice  of 


74 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


bringing  out  their  figures  within  a  few  months  after  the  termination  of 
each  year  and  apparently  sacrifice  nothing  in  accuracy  for  the  sake  of 
commercial  timeliness.  Such  differences  as  appear  in  the  general  table 
are  due  partially  to  discrepancies  in  the  statistics  of  the  production  in  the 
United  States,  for  which  there  are  three  authorities,  whose  reports  are  com- 
pared in  the  following  table: 

PRODUCTION  OF  SPELTER  IN  THE  UNITED   STATES. 
(In  tons  of  2  000  Ib  ) 


Statisticians 

1888 

1889 

1890 

1891 

1892 

1893 

56  000 

59  269 

66  496 

70  632 

86  122 

78  343 

The  Mineral  Industry.  .  . 

55  903 

58  860 

67  342 

80  262 

84  082 

76  255 

U.  S.  Geological  Survey  .... 

55903 

58860 

63683 

80.873 

87  260 

78.832 

Statisticians 

1894 

1895 

1896 

1897 

1898 

1899 

American  Metal  Co  
The  Mineral  Industry  
U.  S.  Geological  Survey  

72  138 
74.004 
75328 

87591 

81  .858 
89686 

81.878 
77.637 
81.499 

98.792 
100  387 
99  980 

114682 
114.104 
115.399 

129.758 
129  6V5 
129051 

The  statistics  of  the  American  Metal  Co.  for  1900  were  123.721  tons;  of  The  Mineral  Industry, 
123231;  and  of  the  U.  S.  Geological  Survey,  123.886.  The  production  of  the  United  btates  in 
1901  according  to  the  U.  S,  Geological  Survey  and  The  Mineral  Industry,  was  140;822  toas. 

It  appears  from  the  above  comparison  that  the  statistics  of  The  Mineral 
Industry  were  probably  about  2,000  tons  too  low  in  1892  and  1893  and 
were  a  good  deal  too  low  in  1895  and  1896,  this  conclusion  being  indicated 
by  the  close  agreement  of  the  reports  for  those  years  by  the  American  Metal 
Co.  and  the  U.  S.  Geological  Survey. 

PRODUCTION    OF    SPELTER    BY' STATES. 
(In  tons  of  2.000  Ib.) 


Year 

N.Jersey 
Penn. 

Virginia 
Tennessee 

Total 
East 

Indiana 

Illinois 

Kansas 

Missouri 

Total 

West 

Grand 
Total 

1882 
1883 
1884 
1885 
1886 
1887 
1888 
1889 
1890 
1891 
1892 
1893 
1894 
1895 
1896 
1897 
1898 
1899 
1900 

5.6< 
5.3^ 
7.8( 
8.0J 
6,7( 
7.4^ 
9,5( 
10,2( 
9,1 
8,945 
9,582 
8,802 
7,400 
9,484 
8,139 
7,218 
8,6 
8,8 
8,2 

)8 

to 

51 
$2 
)2 
16 
U 
>5 
14 
4.217 
4,913 
3.882 
1.376 
3,697 
2.427 
3,365 
31 
35 
59 

5.698 
5.340 
7.861 
8,082 
6,762 
7,446 
9.561 
10.265 
9,114 
13,162 
14,495 
12.684 
8,776 
13,181 
10,566 
10,583 
8.631 
8.805 
8,259 

18.201 
16,792 
17,594 
19,427 
21.077 
22.279 
22,445 
23,860 
26.243 
28,711 
a  3  1,383 
a  29  ,596 
26,799 
31,996 
34,578 
36,370 
44,449 
46,098 
a  38,750 

7.366 
9.010 
7.859 
8,502 
8,932 
11,955 
10.432 
13.658 
15,199 
22.747 
24,715 
22,815 
25,588 
25,775 
20,759 
33  ,396 
40.132 
52,021 
62,136 

2.500 
5,730 
5.230 
4,677 
5.870 
8.660 
13,465 
11,077 
13,127 
16.253 
16;667 
13,737 
11,992 
14,998 
14.001 
18,125 
19,533 
18,107 
78.806 

28.067 
31.532 
30.683 
32606 
35.879 
42.894 
46,342 
48,595 
54,569 
67,711 
72.765 
66.148 
66.552 
76.505 
70,933 
89.397 
106,768 
120,246 
115,627 

33.765 
36.872 
38.544 
40.688 
42.641 
50,340 
55.903 
58.860 
63,683 
80873 
75,328 
89.686 
81  499 
99980 
74,399 
1387.22 
14.115 
129.051 
123,886 





2,173 
3,736 
l',595 
1,506 
2,654 
4,020 

a  Including  Indiana 


STATISTICS    OF    PRODUCTION    AND    PRICES. 


75 


The  statistics  of  the  U.  S.  Geological  Survey  make  a  division  of  the 
production  of  spelter  in  the  United  States  according  to  districts,  which  is 
useful,  although  no  separation  is  made  between  Illinois  and  Indiana.  It 
may  be  arrived  at  with  sufficient  accuracy,  however,  by  taking  for  Illinois 
the  difference  between  the  total  for  the  two  States  as  reported  by  the 
Geological  Survey  and  the  production  of  Indiana  as  reported  by  the 
American  Metal  Co.  This  has  been  done  in  the  above  table. 

PRODUCTION    OP    ZINC    OXIDE    IN    THE    UNITED    STATES. 


Year 

QUANTITY 

VALUE  F.O.B.  WORKS 

TENOR  IN  ZINC  AT  80% 

Short  Tons 

Metric  Tons 

Total 

Per  Short  Ton 

Short  Tons 

Metric  Tons 

1880 

10.107 

9.172 

763,738 

$75-38 

8086 

7338 

1881 

10,000 

9,083 

700,000 

70-00 

8.000 

7266 

1882 

10000 

9.083 

700,000 

70-00 

8,000 

7266 

1883 

12000 

10.899 

840,000 

70-00 

9.600 

8719 

1884 

13000 

11,797 

910  000 

70-00 

10400 

9:438 

1885 

1  5  .000 

13,625 

1  .050  000 

70-00 

12000 

10,900 

1886 

18,000 

16,344 

1  440  000 

SO'OO 

14,400 

13,075 

1887 

18,000 

16,344 

1  440  000 

80  00 

14400 

13  075 

1888 

20  000 

18.149 

1  ,600  000 

80  00 

16000 

14  519 

1889 

16.970 

15,390 

1  .357  600 

80  00 

33576 

12.312 

1890 

•20  000 

*18  140 

1  600,000 

*80'00 

•16000 

*  14  5J2 

1891 

23700 

21496 

1  600  000 

67  51 

18,960 

17  197 

1892 

27  500 

24,946 

2200,000 

80-00 

22000 

19  957 

1893 

25.000 

22678 

1  875  000 

75-00 

20  000 

18  142 

1894 

22,814 

20697 

1,711  275 

75  00 

18  251 

16  554 

1S95 

22690 

20.498 

1  588  300 

70  00 

18  .152 

16  398 

1896 

15  863 

14,391 

1.189,725 

75  00 

12690 

11  5l'J 

1897 

26262 

23825 

1  686  020 

64-20 

21  010 

19060 

1898 

32,747 

29  708 

2226,796 

68-00 

26.198 

23  766 

J899 

39,663 

35982 

3.331  692 

84-00 

31  730 

28786 

1900 

47  151 

42.,?  7  5 

3,772  080 

80  00 

39,721 

34,220 

The  statistics  of  production  and  price  in  the  above  table  from  i860  to  1892  both  years  inclusive, 
are  from  the  reports  of  the  U.  8.  Geological  Survey.  Apparently  the  figures  for  J881-1888  are  approxt 
mate  estimates  rather  than  totals  based  on  reports  from  the  producers  The  statistics  from  1893  to 
]900;  both  years  inclusive,  are  as  reported  by  The  Mineral  Industry  The  figures  marked  with  an 
asterisk  are  estimated. 

The  production  of  zinc  oxide  in  the  United  States,  with  the  exception 
of  an  insignificant  quantity,  is  made  directly  from  ore,  whereas  the  oxide 
produced  in  Europe  is  obtained  by  the  combustion  of  spelter,  its  manu- 
facture in  that  way  constituting  one  of  the  important  channels  of  European 
spelter  consumption.  In  considering  the  relative  importance  of  the  United 
States  as  a  zinc-producing  country,  therefore,  its  production  of  zinc  oxide, 
reduced  to  the  basis  of  its  tenor  in  metallic  zinc,  should  be  added  to  the 
production  of  spelter. 

STATISTICS  or  CONSUMPTION. 

The  only  feasible  method  open  'to  statisticians  in  determining  the 
consumption  of  a  commodity  is  the  combination  of  the  statistics  of  produc- 


f6  PRODUCTION    AND   PROPERTIES    OF    ZINC. 

tion  of  each  country  with  the  movement  into  and  out  of  it  as  shown 
by  the  statistics  of  imports  and  exports.  The  production  plus  the  imports 
indicates  the  total  supply;  deducting  the  exports  from  the  supply  should 
show  the  consumption.  This  method  is  admittedly  inexact,  because  it  takes 
no  account  of  the  stocks  on  hand,  which  may  be  added  to  or  drawn 
from.  The  extension  of  such  statistics  over  a  series  of  years  will,  however, 
indicate  truly  the  amount  and  trend  of  consumption,  inasmuch  as  additions 
to,  or  draughts  upon,  stocks  are  not  cumulative  but  will  balance  in  the 
long  run,  although  the  consumption  for  any  single  year  is  likely  to  be 
inaccurately  measured. 

It  is  not  merely  the  difficulty  mentioned  above  that  perplexes  the  statis- 
tician who  undertakes  to  study  the  consumption  of  such  a  metal  as  spelter : 
he  must  also  decide  how  the  imports  and  exports  are  to  be  classified  and 
tabulated  in  order  to  lead  to  results  which  will  be  commercially  valuable. 
Should  the  statistics  be  based  simply  upon  the  crude  metal?  or  upon  the 
crude  metal  and  all  the  manufactures  thereof?  or  upon  something  inter- 
mediate between  the  two  extremes  ? 

The  statisticians  of  the  Metallgesellschaft,  in  their  valuable  annual  pub- 
lication, compute  the  consumption  first  upon  the  basis  of  the  crude  metal 
alone,  and  compare  the  total  thus  obtained  with  the  statistics  of  production. 
This  is  probably  the  best  that  can  be  done,  because  although  the  statistics 
of  crude  spelter  consumption  do  not  correctly  indicate  the  ultimate 
consumption  of  zinc  in  the  respective  countries,  any  attempt  to  follow  the 
consumption  far  into  the  domain  of  manufacture  would  necessarily  lead  to 
complications  which  could  not  be  easily  avoided.  The  statisticians  of  the 
Metallgesellschaft,  however,  present  supplementary  tables  showing  the  result 
of  such  an  investigation  so  far  as  possible,  which  are  probably  sufficient  for 
all  commercial  purposes.  Those  supplementary  tables  have  been  transcribed 
herein  only  in  so  far  as  sheet  zinc  is  concerned,  inasmuch  as  the  advisability 
of  attempting  to  trace  the  consumption  of  zinc  any  further  is  doubtful.  If 
i'or  example  spelter  is  consumed  in  Germany  for  the  manufacture  of  brass 
\  wares  which  are  subsequently  exported,  it  seems  that  it  may  properly  be 
considered  that  Germany  was  the  place  of  consumption  of  that  spelter, 
irrespective  of  whither  the  brass  wares  may  have  gone.  The  case  of  sheet 
zinc  may  be  regarded  in  a  different  light;  although  it  is  truly  a  manu- 
factured product,  it  is  only  in  the  early  stage  of  manufacture,  in  fact  only 
one  degree  beyond  the  spelter  itself,  and  is  to  a  large  extent  produced  in 
direct  connection  with  the  smelting  process ;  it  would  obviously  be  incorrect 
to  reckon  the  spelter  consumed  for  the  manufacture  of  sheet  zinc  in  Germany 
as  being  entirely  consumed  in  that  country. 


STATISTICS    OF    PRODUCTION    AND   PRICES. 


77 


The  following  tables  of  the  consumption  of  zinc  in  the  various  countries 
ol  the  world,  with  the  exception  of  that  for  the  United  States,  are  taken 
from  the  eighth  annual  report  of  the  Metallgesellschaft,  which  bases  its 
computations  upon  the  statistics  of  production  compiled  by  Henry  K.  Merton 
&  Co.,  but  separated  according  to  political  divisions.  The  table  of  the  con- 
sumption in  the  United  States  has  been  compiled  from  the  statistics  of  The 
Mineral  Industry,  with  corrections  in  the  statistics  of  production  in  1895 
and  1896  as  previously  noted.  In  the  general  table  showing  the  world's 
consumption,  however,  the  figures  for  the  United  States  axe  those  which 
are  used  by  the  Metallgesellschaft. 

CONSUMPTION    OF    ZINC    IN    AUSTRIA  HUNGARY. 

(In  metric  tons  ) 


Year 

1891 

1892 

1893 

1894 

1895^ 

1896 

1897 

1898 

1899 

1900 

Production  .  . 

6542 

5.100 

7.681 

8.715 

8,488 

9.403 

8,314 

7.229 

7.305 

7.026 

Imports  a 

11244 

14,010 

15.083 

15.314 

17.156 

(17.539 

16.599 

17.47J 

15226 

17,844 

Supply  

17.786 

19,110 

22.764 

24.029 

25.644 

26942 

24913 

24,700 

22530 

24872 

Exports  a 

546 

591 

718 

447 

504 

1.256 

770 

1  184 

1.614 

1  080 

Consumption  . 

17.240 

18,519 

22.046 

23,582 

25,140 

25.686 

24.143 

23516 

20,916 

23.788 

a  Inclusive  of  spelter  and  old  zinc. 


CONSUMPTION    OF    ZINC    IN    BELGIUM. 

(In  metric  tons.  > 


Year 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Production.  .  .  . 
Imports  a 

83,751 
3,139 
86890 

87,050 
3,033 
90083 

90,676 
4,956 
95  632 

92,813 
8,354 
101  167 

105,853 
4,455 
110  308 

110,920 
10,000 
120  920 

114^50 
5,000 
119  650 

118,085 
6,700 
124  785 

121,500 
4,200 
125  700 

117,300 
*3,500 
120  800 

Exports  a 
Consumption  a 
Exports  of 
sheet  zinc  .  . 
Net  consump- 
tion   

*54.600 
32,290 

*  18,  000 
14,300 

*55,300 
34,783 

*  17,  000 
17,800 

*60,900 
34,732 

*  18  ,000 
16,700 

*60,600 
40,567 

*18,000 
22,600 

*72,000 
38,308 

*  19,  000 
19,300 

*82,000 
38,920 

*20,000 
18,900 

*8  1,000 
38,650 

*21,000 
17,700 

*85,000 
39,785 

*20,000 
19,800 

*79,000 
46,700 

*20,000 
26,700 

*75,000 
45,800 

*21,000 
24,800 

a  Crude  spelter  only. 


"Estimated. 


CONSUMPTION    OF    ZINC    IN    FRANCE. 

(In  metric  tons.) 


Year 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Production.  .  .  . 

20,298 

20,809 

22,439 

23,090 

26,860 

33,980 

37,239 

37.932 

39,305 

36,329 

Imports  a 

30,243 

29,741 

33,090 

33,256 

25,051 

33,021 

30,201 

32,140 

25,094 

32.894 

Supply  

50,541 

50,550 

55,529 

56,346 

51,911 

67,001 

67,440 

70,072 

64,399 

69,225 

Exports  a 
Consumption  .  . 

1,823 

48,718 

1,993 
48,557 

3,283 
52,246 

3,419 
52,927 

2,644 
49,267 

4,438 
62,563 

3,875 
63,565 

8,816 
61,256 

7,403 
56,996 

6,933 
62,291 

a  Crude  spelter  only. 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


MOVEMENT    OF    SHEET   ZINC    FROM   AND    INTO    FRANCE. 

(In  metric  tons.) 


Year 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Exports  
Imports 

2,966 
205 

3,665 
143 

3,965 
811 

3,176 
396 

3,205 
601 

6,048 
438 

7,102 
1  Oil 

8,379 

202 

7,556 
422 

5,779 
245 

Difference  

2,761 

3,522 

3,154 

2,780 

2,304 

5,610 

6,091 

8,177 

7,134 

5,534 

CONSUMPTION    OF    ZINC    IN    GERMANY. 
(In  metric  tons.) 


Year 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Production.  .  .  . 
Imports  a 

139,353 
7,969 

139,938 
13.021 

142.956 
13,211 

143,577 
17,988 

150,286 
17,542 

153.100 
15,668 

150,739 
18.925 

154,867 
22,771 

153.155 
22  171 

153,350 
22  758 

Supply    .  . 

147,322 

152.959 

156,167 

161,565 

167,828 

168  768 

169  664 

177  638 

175  326 

176  108 

Exports  a 
Consumption  .  . 

57,853 
89,469 

53,287 
99,672 

62,592 
93,575 

61,799 
99,766 

56.933 
110,895 

55,937 
112,831 

49,600 
120.064 

49,471 
128,167 

45.031 
130.295 

50.302 
125.806 

a  Crude  spelter  only. 


MOVEMENT    OF    SHEET    ZINC    FROM    AND    INTO    GERMANY. 

(In  metric  tons.) 


Year 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Exports  
Imports  
Difference.  .  .    . 

15,488 
40 
15,448 

16,304 
48 
16,256 

17,459 
74 
17,385 

16,038 
274 
15,764 

15,921 
128 
15.793 

16,242 
180 
16,062 

17,453 
130 
17,323 

14,477 
53 
14,424 

18,281 
95 
18  186 

16,709 
145 
16  564 

CONSUMPTION    OF    ZINC    IN    GREAT    BRITAIN. 

(In  metric  tons.) 


Year 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Production.  .  .  . 

29.880 

30,794 

28,829 

32.577 

29,965 

25,277 

23,927 

28.386 

32.223 

30.307 

Imports  a 

59,448 

53,638 

57.836 

53,743 

63,525 

77,861 

71.002 

78,711 

71.067 

70.649 

Supply  

89,328 

84,432 

86,665 

86,320 

93,490 

103,138 

94,929 

107,097 

103.290 

100.956 

Exports  a 

8,573 

10,885 

11,623 

10,816 

9,662 

10.487 

8.342 

8.450 

6.520 

8.230 

Consumption.  . 

80,755 

73,547 

75,042 

75,504 

83,828 

92,651 

86,587 

98.647 

96,770 

92,726 

a  Crude  spelter  only. 


MOVEMENT    OF    SHEET   ZINC    FROM    AND    INTO    GREAT    BRITAIN. 

(In  metric  tons.) 


Year. 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Imports  a 
Exports  a 
Difference  

20,480 
1,879 
18,601 

19,260 
1,387 
17,873 

18,716 
1,517 
17,199 

18,841 
1,388 
17,453 

19,670 
1.489 
18,181 

21  ,339 
1,518 
19,821 

21  .395 
1,650 
19745 

21,612 

1,889 
19,723 

21,526 
1.833 
19,693 

22,105 
1.675 
20,430 

a  Classified  in  the  British  statistics  as  manufactures  of  zinc,  but  chiefly  sheet. 


STATISTICS    OF    PRODUCTION    AND    PRICES. 


79 


CONSUMPTION    OF    ZINC    IN    ITALY. 

(In  metric  tons.) 


Year 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Imports  a 
Exports  a 
Consumption  a 
Imports  of 
sheet  zinc  .  .  b 
Total  c 

1,682 
54 
1,628 

3,200 
4,828 

1,583 
8 
1,575 

3.136 
4,711 

1,682 
nil 
1,682 

3.029 
4,711 

2,230 
nil 
2.230 

3.248 
5,478 

2,378 
4 
2,374 

3.137 
5511 

2.596 
33 
2,563 

3.482 
6,045 

3,278 
309 
2,969 

3,556 
6,525 

2,813 
156 
2,657 

3,200 

5,857 

3.498 
227 
3,271 

3,221 
6,492 

3,627 
359 
3,268 

3.543 

6  871 

a  Crude  spelter  only. 

b  Including  other  manufactures  of  zinc. 

c  This  is  equivalent  to  the  total  consumption  of  zinc    in    Italy,  inasmuch    as    the    exports    of 
sheet  zinc'  and  other  manufactures  are  insignificant 


CONSUMPTION    OF   ZINC    IN    RUSSIA. 

(In  metric  tons.) 


Year. 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Production.  .. 

3,821 

4.338 

4.600 

5,100 

5.040 

6.263 

5.853 

5665 

6.324 

5.968 

Imports  a 

4.700 

5.100 

5,000 

5.700 

6.630 

5,650 

7.800 

9,000 

9300 

8600 

Consumption  a 

8,521 

9,438 

9.600 

10,800 

11,670 

11.913 

13,653 

14.665 

15.624 

14,568 

Imports  of 

sheet  zinc.  .  . 

200 

100 

400 

600 

400 

300 

350 

250 

540 

630 

Total  

8,721 

9,538 

10,000 

11,400 

12.070 

12.213 

14,003 

14.915 

• 

16  164 

15.198 

a  Crude  spelter  only. 


CONSUMPTION    OF    ZINC    IN    SPAIN. 
(In  metric  tons.) 


Year 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

Production.  ..  . 
Exports  .    .  .  .a 
Consumption  .  . 

5,656 
2045 
3,611 

5925 
2,762 
3,163 

6,000 
2.500 
3,500 

6.000 
2.680 
3,320 

6.000 
1,367 
4,633 

6.133 
3.561 
2.572 

6.244 
2  171 
4.073 

6.031 
4.553 
1,478 

6.184 
2.701 
3.483 

5785 
2.081 
3704 

a  Includes  sheet  zinc. 


It  will  be  observed  from  the  above  tables  that  Austria-Hungary,  Italy  and 
Russia  have  to  import  a  good  deal  of  spelter  and  export  almost  none  at  all. 
France  and  Great  Britain,  although  large  producers  themselves  and  export- 
ers of  considerable  quantities,  are  obliged  to  make  large  importations  to 
meet  the  home  consumptive  demand.  The  great  exporting  countries  are 
Germany  and  Belgium,  especially  the  latter.  The  small  production  in 
Spain  is  more  than  that  country  produces,  while  Denmark,  Sweden,  Nor- 
way, Switzerland,  Turkey  and  the  Balkan  countries,  which  produce  no 
spelter,  have  to  import  their  entire  supplies. 


PRODUCTION    AND   PROPERTIES    OF    ZINC. 


CONSUMPTION   OF   ZINC    IN   THE    UNITED    STATES. 

(In  tons  of  2,000  Ib.) 


IMPORTS 

Year 

Production 

Spelter 

Sheet 

Total 

Supply 

Exports 

Consump'n. 

1873 

7,343 

3420 

5,561 

8,981 

16,324 

37 

16.287 

1874 

10000 

1,797 

3,008 

4,805 

14,805 

22 

14,783 

1875 

15.833 

1,017 

3,660 

4,677 

20,510 

19 

20,491 

1876 

16000 

474 

2.306 

2,780 

18,780 

67 

18,713 

1877 

17,500 

633 

671 

1  304 

18,804 

720 

18,084 

1878 

19000 

635 

628 

1,263 

20,263 

1.273 

18.890 

1879 

21.000 

710 

556 

1,266 

22,266 

1,066 

21.200 

1880 

23.239 

4.046 

2,035 

6,081 

29,320 

684 

28,636 

1881 

30.000 

1430 

1.364 

2,794 

32794 

746 

32  048 

1882 

33,765 

9i204 

2,207 

11,41.1 

45il76 

745 

44  ,431 

1883 

36.872 

8,534 

1,655 

10  189 

47,061 

426 

46,635 

1884 

38.544 

2!935 

476 

3,411 

41,955 

63 

41  ,892 

1885 

40688 

1,758 

920 

2,678 

43,366 

51 

43.315 

1886 

42,641 

2.150 

546 

2.696 

45,337 

459 

44.878 

1887 

50.340 

4,194 

463 

4,657 

54,997 

68 

54,929 

1888 

55,903 

1,913 

148 

2,061 

57,964 

31 

57,933 

1889 

58,860 

1.026 

507 

1,533 

60,393 

440 

59,953 

1890 

67.342 

1.000 

391 

1,391 

68,733 

1,648 

67,085 

1891 

80262 

404 

11 

415 

80,677 

2,147 

78,530 

1892 

84!082 

149 

14 

163 

84,245 

6,247 

77,998 

1893 

76,255 

213 

14 

227 

76,482 

3,723 

72,759 

1894 

74,004 

194 

20 

214 

74,218 

1,804 

72414 

1895 

87,591 

372 

21 

393 

1,530 

86,454 

1896 

81,878 

520 

14 

534 

10,130 

72,282 

1897 

100.387 

1.453 

8 

1.461 

"  101,  848" 

14,245 

87.603 

1898 

114,104 

1,371 



1,371 

115,475 

10,500 

104,975 

1899 

129,67i 

1,493 

1.493 

131,168 

6.755 

124,413 

1900 

123,231 

1.007 

1  007 

124,238 

22,410 

101,828 

The  world's  consumption  of  zinc  from  1891  to  1900  is  summarized  in  the 
following  table,  compiled  by  the  Metallgesellsehaft,  in  which  its  figures  for 
the  United  States  have  been  retained: 

THE   WORLD'S   CONSUMPTION   OF   ZINC. 

(In  metric  tons.) 


Country 

1891 

1892 

1893 

1894 

1895 

1896 

.1897 

1898 

1899 

1900 

Austiia. 

17  240 

18  519 

22  046 

23582 

25  140 

25  686 

24  143 

23  516 

20  916 

23  782 

Belgium  
France  
Germany  
Great  Britain   . 
Italy  
Netherlands  .    . 
Russia  . 

32,290 
48.718 
89,469 
80,755 
1,628 
*3,600 
8  521 

34,783 
48,557 
99,672 
73,547 
1,575 
*3,600 
9438 

34,732 
52.246 
93,575 
75.042 
1,682 
*3,600 
9  600 

40,567 
52,927 
99,766 
75,504 
2.230 
*3,600 
10  800 

38,308 
49,267 
110,895 
83,828 
2.374 
*3,600 
11  670 

38,920 
62.563 
112,831 
92,651 
2,563 
*3,600 
11  913 

38,650 
63.565 
120,064 
86,587 
2,969 
*3,600 
13  653 

39,785 
61,256 
128,167 
98,647 
2,657 
*3,600 
14  665 

46,700 
56,996 
130,295 
96,770 
3,271 
*3,600 
15  624 

45,800 
62,291 
125,806 
92,726 
3.328 
*3,600 
14  568 

Spain  
United  States.  . 
Other  countries 
Total  
Production.  .  .  . 
Av.  pr.  London 
"       '           '•    a 
"      "     N.  Y.  b 

3,611 
71.327 
*8,000 
365,159 
362,204 
£23* 
5.054 
5.02 

3,613 
73,465 
*9.500 
376,269 
372,900 
£20* 
4.511 
4.63 

3,500 
69,058 
*  13,  000 
378,081 
378,093 
£17| 
3.778 
4.075 

3,320 
64.028 
*8.000 
384.324 
380.877 
£15* 
3.368 
3.52 

4,633 
78.424 
*7,()00 
415,139 
416,621 
£14f 
3.179 
3.63 

2,572 
65,427 
*7,600 
426.326 
424,141 
£16| 
3.615 
3.94 

4,073 
77,778 
*7,000 
442,082 
443,302 

3.805 
4.12 

1,478 
95,711 
*6,500 
475,982 
469,031 
£20i 
4.457 
4.57 

3,483 
112,905 

*7,000 
497,560 
490,205 
£24* 
5.408 
5.75 

3,704 
90.360 
*7,000 
472.965 
478,323 
£20i 
4.402 
4.39 

a  The  average  price  at  London  in  pounds  sterling  per  2,240  Ib. ,  as  reported  by  the  Metallgesell- 
schaft,  has  been  converted  into  dollars  and  cents  per  100  Ib.  at  the  uniform  ra*e  of  £1=$4'87. 
6  Averages  reported  by  The  Mineral  Industry. 


STATISTICS    OF   PRODUCTION   AND   PRICES. 


The  above  table  shows  the  total  consumption  and  production  of  zinc  dur- 
ing the  last  ten  years  to  have  been  as  follows : 


Period. 

1891-1895 

1896-1900 

1891-1900 

Production  
Consumption  .  .  . 

1,910,695 
1.918,972 

2,305,002 
2,314,915 

4,215697 
4.233,887 

itistics  of  consumption  compiled  in  the  manner  of  the  above  introduce 
an  important  factor  the  statistics  of  production.  In  comparing  consump- 
tion and  production,  therefore,  the  chief  reliance  is  in  the  accuracy  of  the 
statements  as  to  imports  and  exports,  inasmuch  as  errors  in  the  statistics  of 
production  are  reproduced  equally  in  the  computations  as  to  total  production 
and  consumption. 

According  to  the  above  statistics  the  consumption  of  zinc  during  the  10 
years  1891-1900  has  been  greater  than  the  production,  whence  the  natural 
inference  is  that  stocks  on  hand  must  have  been  drawn  upon.  In  view 
however,  of  the  really  small  difference  in  the  grand  totals,  that  would 
probably  be  an  unsafe  conclusion,  taking  into  consideration  the  numerous 
chances  of  small  errors  in  the  statistics,  and  the  movement  of  old  metal 
which  may  appear  in  the  reports  of  imports  and  exports  and  be  counted 
twice. 

CONSUMPTION  OF  ZINC  WHITE   IN   THE    UNITED   STATES. 
(In  tons  of  2,000  Ib.) 


X*rt«  - 

TENOR  IN  ZINC  AT  80% 

xear 

Production 

Imports 

Supply 

Exports 

Consumpt'n 

Short  tons 

Metric  tons 

1894 

22,814 

1,686 

24,500 

nil 

24,500 

19,600 

17,777 

1895 

22,690 

2,273 

24,963 

24 

24,939 

19,951 

18,096 

1896 

15,863 

2.286 

18,149 

2,324 

15,825 

12,660 

11,483 

1897 

26,262 

2,782 

29,044 

1,859 

27,185 

21,748 

19,725 

1898 

32,747 

1,671 

34,418 

3,925 

30,493 

24,394 

22,125 

1899 

39,663 

1,506 

41,169 

5,343 

35,826 

28,661 

25,995 

1900 

47,151 

1,309 

48,460 

5,695 

42,765 

34,212 

31,030 

Previous  to  1886  the  only  available  statistics  of  American  imports  and 
exports  of  zinc  white  are  for  fiscal  years  ending  June  30,  which  are  of  course 
useless  for  comparison  with  the  production  reported  for  calendar  years. 

The  imports  entered  in  the  above  table  represent  only  dry  zinc  oxide, 
besides  which  a  small  quantity  of  zinc  oxide  ground  in  oil  is  brought  into 
the  United  States,  the  quantity  of  the  latter  product  being  65  tons  in  1895, 
155  tons  in  1896,  251  tons  in  1897,  13  tons  in  1898  and  21  tons  in  1899. 

Previous  to  1897  the  exports  reported  above  include  zinc  ore,  correspond- 


82 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


ing  to  "  oxide  and  ore  "  of  the  IT.  S.  Bureau  of  Statistics  enumeration.  There 
was,  however,  but  little  ore  exported  before  1897,  when  large  shipments  from 
New  Jersey  first  began  to  be  made. 

The  imports  of  zinc  white  into  the  United  States  and  the  supply  from 
1885  to  1894  were  as  follows  (in  tons  of  2,000  lb.) : 


Year.         

1886 

1887 

1888 

1889 

1890 

1891 

1892 

1893 

Production  

18,000 

18,000 

20,000 

16  970 

20  000 

23  700 

27  500 

25  000 

Imports. 

1  763 

2  481 

701 

1  343 

1  316 

1  420 

1  221 

1  950 

Supply  

19763 

20,481 

20,701 

18  313 

21  316 

25  120 

28  721 

26  950 

STATISTICS  OF  PRICE. 

The  chief  markets  of  the  world,  wherein  the  prices  which  govern  the 
zinc  industry  are  established,  are  New  York,  London  and  Breslau.  The 
price  made  in  London  practically  governs  the  industry  in  Europe,  although 
the  business  in  Upper  Silesia  is  transacted  on  the  basis  of  the  price  at 
Breslau;  the  latter  generally  preserves,  however,  a  certain  relation  to  the 
London  price.  Similarly  in  the  United  States  the  business  of  the  Kansas- 
Missouri  district  is  transacted  on  the  basis  of  the  price  of  spelter  at  St. 
Louis.  The  St.  Louis  price,  however,  corresponds  with  the  New  York 
price,  minus  the  difference  in  the  cost  of  transportation  to  the  two  points. 
That  difference  is  not  merely  the  freight  rate  from  St.  Louis  to  New  York, 
but  is  the  variation  between  the  rates  from  Kansas  smelting  points  to  New 
York  and  St.  Louis  respectively.  For  example,  at  the  present  time  (1901) 
the  rate  on  spelter  from  lola  to  New  York  is  $0-34  per  100  lb. ;  and  from 
lola  to  St.  Louis,  $048  per  100  lb.  The  difference  between  the  New  York 
and  St.  Louis  prices  should,  therefore,  be  normally  $0-1()  per  100  lb. ; 
practically  the  difference  during  1901  has  been  $0-15  most  of  the  time.  The 
difference  between  the  New  York  and  St.  Louis  price  varies  consequently 
from  time  to  time  according  to  the  freight  rates,  taking  into  account 
rebates,  etc.,  which  may  be  allowed  by  the  railways.  There  are  no  available 
statistics  of  the  average  price  at  St.  Louis  for  a  long  period  of  years,  but 
considering  the  last  ten  years  it  would  probably  be  nearly  correct  to  reckon 
it  as  having  been  $0-20  per  100  lb.  below  the  New  York  price. 

Although  the  importation  of  spelter  into  the  United  States  from  Europe 
is  practically  prohibited  by  the  tariff  of  l-5c.  per  lb.,  and  the  American 
price  of  spelter  is  consequently  to  a  considerable  extent  independent  of  the 
European  price,  there  is  nevertheless  at  many  times  an  intimate  relation 
between  the  prices  of  the  two  Continents,  because  of  the  ability  of  American 
producers  to  export  zinc  at  a  profit  under  certain  conditions.  The  freight 


STATISTICS    OF    PRODUCTION    AND    PRICES. 


83 


rate  on  spelter  from  lola  to  Liverpool  is  now  $0-35  per  100  Ib.  (within  five 
years  or  so  it  has  been  as  low  as  $0-22  per  100  Ib.).  Consequently  if  at 
any  time  the  price  of  spelter  at  London  rises  materially  above  the  price  at 
New  York  and  there  be  an  excess  of  productive  capacity  in  the  United  States, 
which  generally  there  is,  the  exportation  of  spelter  from  Kansas  to  Europe 
tends  to  reduce  the  European  price  to  the  American  level. 

The  average  monthly  price  of  spelter  at  New  York  and  the  average  annual 
price  at  London  and  in  the  principal  markets  of  Germany,  for  a  long  period 
of  years,  are  given  in  the  subjoined  tables.  The  New  York  prices  are  as 
quoted  by  The  Mineral  Industry;  the  authorities  for  the  English  and  Ger- 
man prices  are  stated  in  each  case. 

AVERAGE    MONTHLY    PRICE    OF    PRIME     WESTERN    SPELTER    AT    NEW    YORK, 

IN    CENTS    PER    POUND. 


Jan. 

Feb. 

Mar. 

April 

May 

June 

July 

Aug. 

Sept. 

Oct. 

Nov. 

Dec. 

Year 

1875 

6'56 

6'46 

6  '35 

6  '75 

7'20 

7'20 

7'30 

7  '175 

7  '175 

7  '275 

7  "275 

7  '275 

7  '00 

1876 

7  '50 

7  '625 

7  '685 

7'80 

7  '875 

7  '625 

7  '185 

7  '125 

6'96 

6  '685 

6  '495 

6  '435 

7'25 

1877 

6  '375 

6  '56 

6  '435 

6'3t 

6  '125 

5  '995 

5  '745 

5*85 

5'81 

5'80 

5  '745 

5  '625 

6'03 

1878 

5  '625 

5  '435 

5  '435 

5  '125 

4'81 

4  '  435 

4  '625 

4  '685 

4'81 

4'66 

4  '625 

4"31 

4'88 

1879 

4  '375 

4'51 

4  '495 

4'50 

4'375 

4  '245 

4'56 

5'21 

5'81 

6  '185 

6'06 

6  '125 

5  '036 

1880 

6  185 

G'56 

6  '625 

6'3L 

5'81 

5'3L 

4  '935 

5'06 

4-935 

4-935 

4-775 

4'  70 

5'51 

1881 

5  '06 

5  '185 

4  '935 

4-935 

5  '935 

4  '875 

4  '875 

5'06 

5  '125 

5'31 

5  '685 

5  '935 

5  '243 

1882 

5  '875 

5  '685 

5  '495 

5  '375 

5  '435 

5'31 

5  '245 

5'31 

5  '245 

5  '245 

4  '995 

4  '685 

5  '325 

1883 

4'56 

4  '56 

4  '685 

4  '675 

4  '625 

4  '495 

4'40 

4'35 

4'45 

4'40 

4  '385 

4'36 

4-495 

1884 

4  '285 

4  '325 

4'50 

4  575 

4  '525 

4-455 

4'50 

4-57 

4'  56 

4-475 

4'35 

4'125 

4'443 

1885 

4'31 

4  "275 

4'21 

4'21 

4'175 

4'  05 

4'25 

4'50 

4"56 

4'56 

4'525 

4  '525 

4  345 

1886 

4'40 

4  '425 

4'55 

•4'55 

4'50 

4-375 

4-35 

4-35 

4  '325 

4  '275 

4  '275 

4  '425 

4'40 

1887 

4  '55 

4'  55 

4-475 

4'45 

4-55 

4-55 

4-575 

4-55 

4'  50 

4'525 

4-775 

5'40 

4  '625 

1888 

5  '425 

5'35 

5'  10 

4  '85 

4'65 

4-55 

4-55 

4-75 

4-975 

5'05 

4'90 

4  '875 

4'91 

1889 

5'00 

4  '95 

4'75 

4'675 

4'75 

4-975 

5  "10 

5'20 

5'175 

5'10 

5'20 

5'40 

5  '023 

1890 

5'4l 

5'28 

5  187 

5'085 

5-35 

5-575 

5'55 

5'275 

5'06 

6'012 

6'122 

6'106 

5'55 

1891 

5  '55 

5  025 

5   125 

5'  00 

4  '85 

5  "083 

5  "063 

5'01 

4  "958 

5'02 

4'83 

4-75 

5'02 

1892 

4'69 

4'62 

4'  89 

4'68 

4-79 

4'71 

4'78 

4'69 

4-53 

4'41 

4-47 

4'40 

4'63 

1893 

4  "39 

4  '33 

4'28 

4'  38 

4'41 

4'27 

4'13 

3'89 

3"69 

3'68 

3'65 

3'80 

4  '075 

1894 

3'56 

3'85 

3'89 

3'62 

3'47 

3"40 

3'43 

3'38 

3-44 

3  45 

3'36 

3'43 

3  '52 

1895 

3'28 

3'20 

3  '23 

3  30 

3'50 

3'65 

3'75 

4'15 

4'  30 

4'10 

3'55 

3'49 

3'63 

1896 

3'75 

4  '03 

4'20 

4"  09 

3  "98 

4'  10 

3'97 

3'  76 

3'60 

3'72 

3'99 

4'14 

3'94 

189/ 

3  91 

4'02 

4   12 

4'13 

4'21 

4'2l 

4  "32 

4  26 

4'18 

4'17 

4'03 

3'89 

4'12 

189S 

3'96 

4'04 

4  '25 

4  '26 

4'27 

4'77 

4'66 

4'58 

4'67 

4  '98 

5  29 

5'10 

4'57 

1899 

5'34 

6"  28 

6  '31 

6'67 

6'88 

5'98 

5  '82 

5'65 

5'  50 

5'32 

4'64 

4'66 

5'75 

1900 

4'65 

4'64 

4'60 

4'71 

4  '53 

4  '29 

4'28 

4'17 

4'11 

4'15 

4'29 

4'25 

4'39 

1901 

4'  13 

4'01 

3'9l 

3'98 

4'D4 

3'99 

3'95 

3'99 

4'08 

4'23 

4'29 

4'31 

4'08 

AVERAGE    ANNUAL    PRICE    OF    ORDINARY    SILESIAN    SPELTER    AT    LONDON, 
PER    TON    OF    2,240    LB. 

(From  statistics  oi  the  Metailgesellschaft.') 


£   s.   d. 

£   s.  d. 

£   s.   d. 

£   s.  d. 

1869 

20   7   4 

1877 

19  18   8 

1885 

13  19  11 

1893 

17   8   0 

1870 

18  10   4 

1878 

17  17  10 

1886 

14   5   1 

1894 

15   9   2 

1871 

18   8   9 

1  1879 

16  12   0 

1887 

15   4   0 

1895 

14  12   2 

1872 

22   9   1 

1880 

18   7   1 

1888 

18   1   9 

1896 

16  11  10 

1873 

26   3   6 

1881 

16   5   6 

1889 

19  15   7 

1897 

17   9  10 

1874 

22  17   7 

issr 

16  19   9 

1890 

23   4   6 

1898 

20   8   9 

1875 

24   1   4 

1883 

15   6   6 

1891 

23   4   8 

1899 

24  17   2 

1876 

23   6   3 

1884 

14   8  11 

1892 

20  16   6 

1900 

20   5   6 

The  average  pirce  of  Silesian  spelter  at  London  in  1901  was  £17  Os.  7d. 


84 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


AVERAGE  ANNUAL  PRICE  OF  ENGLISH   SPELTER  AT  LONDON, 

PER  TON  OF  2,240  LB. 
(From  British  blue  books  on  mines  and  minerals  in  the  United  Kingdom.) 


£   s.  d. 

£   s.  d. 

£  s.   d. 

£  s.   d. 

1872 

22  14   9 

1880 

19   3   9 

1888 

19   2  10 

1896 

17   6   8 

1873 

26  16   6 

1881 

16  17   8 

1889 

20   9   2 

1897 

17  19  10 

1874 

23   6   9 

1882 

17  15   6 

1890 

23  13  11 

1898 

20  18   8 

1875 

24   5   0 

1883 

16   1   0 

1891 

23  18   5 

1899 

25   6   2 

1876 

23   7  11 

1884 

15   8   2 

1892 

21  15   9 

.... 

1877 

21  15   0 

1885 

14  18  10 

1893 

17   8   0 

1878 

19   9   9 

1886 

15  14   0 

1894 

16   2   4 

.  .  .  . 

1879 

17   5   0 

1887 

16   1   5 

1895 

15   5   8 

AVERAGE    YEARLY    PRICE    OF    SPELTER    IN    THE    PRINCIPAL    MARKETS    IN 

GERMANY,  a 
(Price  in  marks  per  100  kg. ;  1  mark=23-8  cents.) 


BRESLAU 

COLOGNE 

FRANKFURT 

HALBERSTADT 

HAMBURG 

Year 

Good  Silesian 
from  works 

Rhenish  brands 
W.H.  and  S.S. 
3mos. 

Refined  calamine 
and  blende  from 
works 

Rhenish  and 
Westphalian, 
crude,  from 
works,  1  to  3  mos 

Silesian  in 
slabs 

1879 

34-27 

36-38 

32-44 

35-14 

1880 

'.'.'.'.. 

37-88 

38-47 

36-23 

38-61 

1881 

32-66 

33-53 

31-09 

32-57 

1882 

34-32 

34-88 

33-84 

35-04 

1883 

28  :60 

30-58 

31-35 

30-19 

31-68 

1884 

27-20 

29-00 

29-06 

28-66 

30-16 

1885 

26-08 

28-14 

27-91 

27-68 

28  'CO 

1886 

26-71 

28'64 

28-03 

28-11 

29-58 

1887 

28-38 

30-47 

29-96 

29-88 

31-23 

1888 

35-41 

37-21 

36-02 

36-10 

39-26 

1889 

38-25 

40-56 

39-68 

39-48 

41-55 

1890 

45-11 

47'92 

47-02 

46-58 

49-27 

1891 

44-98 

47-34 

46-44 

46-54 

48-95 

1892 

40-54 

43-08 

42-17 

42-23 

45-30 

1893 

33-60 

35-78 

35-13 

34-42 

38-07 

1894 

29-90 

32-40 

30-90 

30-90 

34-30 

1895 

28-30 

30-20 

29-20 

29-30 

31-90 

1896 

31-60 

34-00 

33-20 

32-20 

34-60 

1897 

33-90 

36-00 

35-30 

34-70 

37'00 

1898 

39'SO 

41-80 

41-70 

41-40 

43-20 

1899 

48-10 

51-40 

50-50 

50-00 

51-90 

1900 

39'46 

42-97 

41-31 

41-12 

42-50 

a  From   Vierteljahrshefte  zur  Statistik  des  Deutschen   Reichs. 


Equivalent  Prices  of  Spelter  in  Pounds  Sterling  per  2,21+0  lb.,  Marks  per 
100  leg.  and  U.  S.  Currency  per  100  Ib. 

The  price  of  spelter  (or  any  other  commodity)  quoted  in  pounds  sterling 
per  2,240  Ib.  can  be  converted  into  the  equivalent  in  U.  S.  currency  per 
100  Ib.  by  the  following  formula  : 


in  which 

P=price  per  100  Ib.  in  dollars  and  cents. 

F=price  in  pounds  sterling,  shillings  and  pence  being  expressed  in  deci 
mal  parts  of  a  pound. 

E=the  value  of  £1  in  U.  S.  currency—  i-  e.,  at  the  current  rate  of  exchange. 


STATISTICS    OF    PRODUCTION    AND    PRICES. 


85 


For  example,  the  equivalent  of  £22  10s.  6d.  per  2,240  Ib.  in  dollars  and 
cents  per  100  Ib.,  when  exchange  is  at  $4-866,  is  computed  as  follows : 

£22  10s.  6d.=£22-525 
£22-525X4-866-^22-4=$4-983 

In  the  same  manner  the  equivalents  of  £14  to  £29  at  rates  of  exchange  of 
$4-83  to  $4-89,  with  intervals  of  £1  and  Ic.  respectively,  have  been  calculated 
in  the  following  table: 

EQUIVALENT  PRICES  IN  POUNDS  STERLING  PER  2,240  LB.  AND  DOLLARS  AND 
CENTS    PER    100    LB.    AT    DIFFERENT    RATES    OF    EXCHANGE. 


£  1  - 

$4-83 

$4'84 

$4'85 

$4-86 

$4-87 

$4-88 

$4-89 

Increase 

£14 

t$3-019 

t$3  '  025 

$3-031 

$3-038 

$3-043 

t$3'050 

$3-056 

0-6250 

15 

3-234 

3'241 

3-248 

3  254 

3-259 

3-268 

3-275 

0*6696 

16 

t3-450 

3-457 

3-464 

3-471 

3*479 

3-486 

3-493 

0-7143 

17 

3-666 

3-673 

3'681 

3-688 

3-696 

3-704 

3-711 

0-7589 

18 

3-881 

3-889 

3-897 

3-905 

3-913 

3-922 

3-929 

0-8035 

19 

4-097 

4-105 

4-114 

4-122 

4-131 

4-139 

4-148 

0-8482 

20 

4'313 

4-321 

4-330 

4-339 

4-348 

4-357 

4-366 

0-8927 

21 

4-528 

4-538 

4-547 

4-556 

4-566 

t4'575 

4-584 

G'9375 

22 

4-744 

4-754 

4-763 

4-773 

4-783 

4-793 

4-803 

0-9821 

23 

4-959 

4-970 

4-980 

4-990 

5-000 

5-011 

5-021 

•0268 

24 

J5-175 

5-186 

5-196 

5  207 

5-218 

5'229 

5'239 

•0714 

25 

5-391 

5-402 

5-413 

5-424 

5*435 

5-446 

5-458 

•1161 

26 

5'60G 

5-618 

5-629 

5-641 

5-653 

5-664 

5'676 

•1607 

27 

5-822 

5-834 

5-846 

5'857 

5'870 

5-882 

5-894 

•2054 

28 

6  038 

t6  '  050 

6-063 

t6-075 

6-088 

16-100 

6-113 

•2500 

29 

6-253 

6-266 

6'279 

6  '  292 

6'305 

6-318 

6-331 

•2946 

Increase 

21  '  5625c. 

21-6071c. 

21-6518c. 

21  6964c. 

21-7411c. 

21-7857c. 

21'8304c. 

0-0446 

The  figures  marked  with  daggers  in  the  above  table  are  absolutely  correct, 
the  dividend  giving  with  the  divisor,  22-4,  the  quotient  as  entered,  without 
remainder.  The  other  figures  in  the  table  involve  errors  to  the  maximum 
extent  of  plus  or  minus  $0-0005=lc.  per  2,000  Ib.  The  extreme  right 
hand  column  gives  the  differences  in  cents  per  100  Ib.  caused  by  fluctuations 
of  Ic.  in  the  rate  of  exchange,  from  which  the  equivalents  of  prices  at 
intermediate  rates  of  exchange  can  be  found  by  interpolation.  At  the  foot 
of  each  column  headed  by  the  rate  of  exchange  is  given  the  difference  in  cents 
per  100  Ib.  caused  by  a  difference  of  £1  per  2,240  Ib.,  from  which  the 
equivalents  of  fractional  values  can  be  quickly  arrived  at  by  interpolation. 
It  may  be  assumed  roughly  that  a  difference  of  Is.  per  2,240  Ib.  corresponds 
to  Ic.  per  100  Ib.,  6d.— 0-5c.  and  3d.=0-25c.  for  all  rates  of  exchange 
between  $4-83  and  $4-89.  In  determining  the  equivalent  of  a  fractional 
price  with  an  intermediate  rate  of  exchange  with  absolute  accuracy  a  double 
interpolation  must  be  made. 

The  German  mark  being  equivalent  to  23-8c.  U.  S.  currency,  at  par  of 
exchange,  and  one  kilogram  being  equal  to  2-2046  Ib.,  a  difference  of  one 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


mark  per  100  kg.  corresponds  to  10-8c.  per  100  Ib.  The  quotation  of 
40  marks  per  100  kg.  is  equivalent,  therefore,  to  $4-32  per  100  Ib.  In 
order  to  convert  a  quotation  in  marks  per  100  kg.  into  the  equivalent  dollars 
and  cents  per  100  Ib.,  multiply  the  number  of  marks  by  0-108 ;  thus : 

48-lXO-108=5-19. 

For  convenient  comparison  of  the  prices  of  spelter  at  New  York  and 
London,  and  at  the  works  in  Upper  Silesia,  the  averages  reported  in  pounds 
sterling  per  long  ton  and  marks  per  100  kg.  have  been  reduced  in  the  follow- 
ing table  to  the  common  basis  of  cents  per  pound.  The  statistics  for  New 
York  have  been  taken  from  The  Mineral  Industry;  those  for  London  rep- 
resent the  price  of  ordinary  Silesian  spelter  as  reported  by  the  Metallgesell- 
schaft;  and  those  for  Silesia  are  from  the  Statistik  des  Oberschlesischen 
Berg-  und  Huttenmannischen  Vereins.  The  last  have  been  used  rather  than 
the  official  statistics  of  the  German  Government  because  they  agree  closely 
with  the  latter  and  go  further  back. 

AVERAGE  ANNUAL  PRICE  OF  SPELTER  IN  VARIOUS  MARKETS,  REDUCED  TO 

CENTS    PER    POUND. 


Year 

New  York 

London 

Silesia 

Year 

New  York 

London 

Silesia 

1871 

4-008 

3-856 

1886 

4-400 

3-097 

2-765 

1872 

4-881 

4-406 

1887 

4-625 

3-302 

2'970 

1873 

5-691 

5'162 

1888 

4-910 

3-932 

3-499 

1874 

4-973 

4-568  ' 

1889 

5-023 

4-299 

3'877 

1875 

7  :666 

5-232 

4-903 

1890 

5-550 

5-048 

4*752 

1876 

7'250 

5-068 

4-655 

1891 

5-020 

5-049 

4*763 

1877 

6-030 

4-333 

3-974 

1892 

4-630 

4-527 

4-169 

1878 

4-880 

3-888 

3-478 

1893 

4-075 

3-783 

3-499 

1879 

5-036 

3'609 

3'240 

1894 

3-520 

3-359 

3-067 

1880 

5*510 

3-989 

3-672 

1895 

3-630 

3-175 

2-916 

1881 

5-243 

3'538 

3-283 

1896 

3-940 

3-608 

3-229 

1882 

5-325 

3-693 

3-413 

1897 

4-120 

3-803 

3-542 

1883 

4-495 

3-329 

3-056 

1898 

4-570 

4-443 

3-996 

1884 

4-443 

3-140 

2-884 

1899 

5-750 

5-405 

5-033 

1885 

4-345 

3'043 

2-732 

1900 

4-390 

4*407 

4-201 

It  will  be  observed  from  the  above  table  that  the  price  of  spelter  has  been 
subject  to  wide  fluctuations,  especially  in  the  United  States,  where  the  range 
has  been  from  7-875c.  (the  average  for  May,  1876)  to  3-20c.  (the  average 
for  February,  1895 ).1  The  maximum  price  was  attained  at  a  time  when 
the  market  was  controlled  by  a  combination  of  producers  which  was  organ- 
ized for  the  purpose  of  enhancing  the  value  of  spelter  and  was  temporarily 
successful  in  doing  so.  The  minimum  price  was  quoted  during  the  period 
of  depression  which  followed  the  panic  of  1893. 

1TMs  statement  covers  the  period  from  Jan.  1,  1875,  to  Dec.   31,   1901.     In  February, 
1895,  spelter  touched  2-90c.  at  St.  Louis. 


STATISTICS    OF   PRODUCTION    AND   PIJICES. 


87 


It  is  a  common  practice  in  considering  statistics  of  price  to  compare  the 
average  of  a  single  year  with  the  average  of  the  previous  10  years.  Such 
decennial  averages  have  been  computed  for  each  year  in  the  following  table: 

AVERAGE    PRICE    OF    SPELTER    FOR    DECENNIAL    PERIODS,    REDUCED    TO 
CENTS    PER    POUND. 


Ten  years 
ending 

New  York 

London 

Silesia 

Ten  years 
ending 

New  York 

London 

Silesia 

1871 

3  947 

1886 

972 

3  566 

3  250 

1872 

4  047 

1887 

832 

3  463 

3  149 

1873 

4  224 

1888 

835 

3  467 

3  151 

1874 

4  253 

1889 

833 

3  536 

3  215 

1875 
1876 
187? 
1878 
1879 

:  ".'.'.".  '.'. 

"A  703 
4  653 
4  57) 

4  331 
4  373 
4'350 
4  290 
4  201 

1890 
1891 
1892 
1893 
1894 

837 
815 
•745 
'703 
'611 

3  642 
3  793 
3  877 
3  922 
3  944 

3  323 
3  471 
3  547 
3  591 
3  609 

1880 

4  567 

4  191 

1895 

539 

3  957 

3  628 

1881 
1882 
1883 
1884 
1885 

"5  522 
5  257 

4  520 
4  401 
4  165 
3-982 
3  763 

4-134 
4  035 
3  824 
3  656 
3-439 

1896 
1897 
1898 
1899 
1900 

493 
442 
408 
481 
4-365 

4  008 
4  058 
•4  109 
4  220 
4  156 

3  674 
3  731 
3  781 
3  897 
3  842 

The  production  of  zinc  in  Europe,  which  was  inaugurated  during  the  first 
decade  of  the  nineteenth  century,  did  not  attain  much  importance  until 
about  1840,  in  which  year  it  was  probably  not  to  exceed  20,000  metric  tons. 
The  next  decade  witnessed  a  great  expansion  and  in  1850  the  production  was 
50,000  tons,  or  close  to  it.  In  1860  it  was  somewhat  more  than  85,000  tons. 
From  1831  to  1840  the  average  price  of  spelter  in  Upper  Silesia  was  26-08 
marks  per  100  kg.;  from  1841. to  1850  it  was  36-34;  from  1851  to  1860  it 
was  36-84.  The  annual  price  since  1860  may  be  found  from  the  tables  im- 
mediately preceding  this  paragraph  and  from  the  table  of  ore  production  in 
Upper  Silesia  in  the  early  part  of  this  chapter.  An  account  of  the  fluctua- 
tions in  price  previous  to  1841  may  be  found  in  Chapter  I. 

Between  1841  and  1860  the  price  of  spelter  varied  a  good  deal.  By  1840 
the  Silesian  zinc  industry  had  recovered  from  the  crisis  of  1829,  when 
spelter  sold  at  18  marks  per  100  kg.  at  Breslau  (the  lowest  recorded  price), 
and  having  been  established  on  a  sounder  basis  the  increasing  demand  began 
to  outstrip  the  production,  leading  to  a  range  of  prices  from  32  to  52 
marks.  The  political  disturbances,  which  arose  in  most  parts  of  Europe  in 
1848,  upset  the  market  and  from  1848  to  1852  the  price  ruled  at  22  to  27 
marks.  From  1852  to  1870,  and  later,  there  was  steady  prosperity  in  the 
business  and  a  general  upward  tendency  in  price.  Probably  about  the  same 
conditions  existed  in  the  other  zinc-producing  districts  of  Europe  as  in 
Upper  Silesia,  but  anyway  Upper  Silesia  was  the  most  important  market, 
inasmuch  as  up  to  about  1870  its  works  made  50%  or  more  of  the  total 


88  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

production  of  Europe,  or  it  might  be  said  of  the  world  since  the  output  of 
the  United  States  was  of  no  consequence  prior  to  that  time. 

It  is  to  be  observed  then  that  from  the  minimum  price  of  18  marks  per 
100  kg.  (l-944c.  per  Ib.)  in  1829,  there  was  in  spite  of  temporary  ups  and 
downs  a  gradual  rise  to  the  maximum  of  5-162c.  in  1873.  In  the  early  part 
of  that  period  of  44  years  the  consumptive  demand  for  the  still  compara- 
tively new  metal  was  small,  and  the  facilities  for  producing  it  were  great. 
The  supply  of  ore  was  obtained  from  near  the  surface,  and  it  was  of  high 
grade  and  docile  in  smelting.  In  the  latter  part  of  that  period  the  demand 
for  the  metal  had  greatly  increased,  but  the  cost  of  production  had  also  in- 
creased, and  the  demand  could  be  supplied  only  at  a  higher  range  of  prices. 
We  have  it  on  the  authority  of  the  Bergwerksgesellschaft  Georg  von 
Giesche's  Erben  that  in  the  50  years  from  1834  to  1883  the  cost  of  produc- 
tion per  centner  of  zinc  more  than  doubled  itself,  the  greater  poverty  of  the 
ore  and  the  increase  in  wages  and  the  price  of  coal  more  than  offsetting 
the  economy  in  labor  and  coal  and  the  other  improvements  in  the  metal- 
lurgical practice. 

The  decline  in  the  price  of  spelter  which  began  in  1874  and  continued, 
with  only  two  checks,  until  1885  is  atttributable  chiefly  to  the  new  supply  of 
rich  ore  that  in  1870  began  to  be  offered  in  the  form  of  blende.  At  about 
the  same  time  the  United  States  began  to  be  an  important  producer  of  zinc, 
its  importations  from  abroad  dwindled  down,  and  this  outlet  for  European 
spelter  gradually  became  closed.  Simultaneously  there  was  a  heavy  increase 
in  the  world's  production.  Up  to  1870  the  spelter  product  of  Europe  was 
derived  almost  exclusively  from  calamine.  Blende  had  been  mined  and 
smelted  in  Belgium  as  early  as  1845,  but  the  output  of  that  Kingdom 
never  attained  much  magnitude.  The  Belgian  production  of  calamine  had 
been  on  the  wane  since  1856.  In  1870  the  Scharley  and  Marie  mines, 
which  had  previously  been  the  most  important  producers  in  Upper  Silesia, 
came  to  the  end  of  their  resources,  but  in  the  same  year  the  blende  of  the 
district  began  to  be  utilized,  although  its  production  did  not  assume  large 
proportions  until  nearly  10  years  later. 

The  abnormally  high  prices  for  spelter  in  the  United  States  in  1875 
and  1876  were  to  a  large  extent  artificial,  being  due  to  the  manipulations  of 
a  combination  of  the  western  producers,  which  was  formed  in  the  spring  of 
1875.  In  April,  1876,  it  succeeded  in  raising  the  nominal  price  of  spelter 
to  8c.,  New  York,  but  production  had  been  stimulated,  consumption 
restricted  and  stocks  accumulated,  so  that  in  June,  1876,  the  combination 
was  practically  disrupted,  this  being  followed  by  a  rapid  decline  in  the 
price.  In  1879  and  1882  syndicates  to  control  production  and  price  were 


STATISTICS    OF   PRODUCTION    AND   PRICES. 


89 


organized  in  Europe,  but  their  efforts  were  of  only  temporary  effect  on  the 
market,  which  continued  to  sag  under  the  weight  of  the  heavy  production. 
During  the  decade  1881-1890  the  exports  of  spelter  from  Europe  to  the 
United  States  again  became  of  considerable  importance,  attaining  a  max- 
imum of  11,411  short  tons  in  1882  (in  which  year  the  American  production 
was  33,765  tons),  but  since  1887  foreign  spelter  has  ceased  to  be  of  any 
consequence  in  the  American  market.  In  1888  there  was  formed  in  Europe 
:i  combination  of  the  French,  German,  and  British  producers  to  restrict 
production,  which  went  into  effect  in  1889  and  continued  to  the  end  of  1894. 
This  was  probably  the  best-sustained  effort  to  regulate  the  price  of  spelter, 
but  although  it  had  a  temporary  influence  on  the  market  it  could  not  prevent 
production  by  new  concerns,  who  were  led  into  the  business  by  the  attraction 
of  high  prices  and  large  profits,  and  its  ends  were  thus  defeated. 

Since  1890  the  predominant  features  in  the  zinc  market  have  been  the 
sagging  of  prices  under  increasing  production  in  the  early  part  of  the 
decade;  the  enormously  increasing  production  in  the  United  States  and 
the  beginning  (in  1896)  of  large  exports  to  Europe;  the  decrease  in  the  cost 
of  smelting  in  the  United  States  because  of  the  utilization  of  the  natural- 
gas  resources  of  Kansas  and  improvements  in  the  metallurgical  practice; 
and  the  increase  in  the  cost  of  smelting  in  Europe  because  of  the  rise  in 
the  value  of  coal,  especially  toward  the  end  of  the  decade.  There  was  a 
period  of  industrial  depression  in  both  Europe  and  America  in  1893  to 
1895;  and  a  recovery,  which  culminated  in  a  boom  in  1899  and  the  early 
part  of  1900;  followed  by  a  depression  in  Europe,  which  caused  a  great 
decline  in  the  price  of  spelter  there,  and  sympathetically  a  corresponding 
decline  in  the  price  in  the  United  States,  although  the  period  of  general 
industrial  prosperity  continued  here.  It  will  be  observed,  from  the  accom- 
panying tables  how  since  1890  the  American  price  for  spelter  has  preserved 
a  rather  constant  relation  to  the  European  price,  although  spelter  in  Europe 
can  no  longer,  under  normal  conditions,  enter  the  American  market. 

AVERAGE    MONTHLY    PRICE    OF    ZINC    BLENDE    ORE    AT    JOPLIN,    MO. 

(Price  per  2.000  Ib.  of  ore,  in  producers'  bins.) 


Yr. 

Jan. 

Feb. 

Mar. 

April 

May 

June 

July 

Aug.  !   Sept. 

Oct. 

Nov. 

Dec. 

12mos. 

1896 

$24.00 

$23.50 

$23  .  00 

$23  .  00 

$21.50 

$21.00 

$21.50 

$21.00$20.00 

$20.50 

$23.50 

$25.50 

$22.33 

18971  22.125 

21.50 

21.00 

21.125 

21.60 

21.875 

22.  50 

22.50 

22.625 

22.75 

23.50 

24.25 

22.28 

1898 

23.00 

22.50J  23.00 

24.62 

26.50 

28.50 

28.00 

28.37 

31.00 

33.70 

36.25 

37.00 

28.44 

1899    32.25 

43.37    43.40 

51.50 

50.50 

45.50 

44.  2C 

45.00 

43.75 

43.50 

35.00 

36.00 

38.54 

1900    30.23 

29.36!  28.451  28.42 

26.92 

25.00 

24.23 

25.67 

24.25 

24.25 

24.45 

25.40 

26.50 

1901    23.73 

23.96 

23.70 

24.58 

24.38   24.22 

24.68 

23.88 

22.82 

21.63 

26.15 

28.24 

24.21 

The  statistics  of  the  above  table  are  taken  from  various  volumes  of  The 


90 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


Mineral  Industry  with  the  exception  of  those  for  1900  and  1901,  for  which 
years  the  values  reported  by  the  U.  S.  Geological  Survey  have  been  adopted. 
The  Mineral  Industry  and  the  U.  S.  Geological  Survey  agree  as  to  the  values 
for  the  years  "1896-1899,  both  inclusive.  There  are  no  complete  statistics 
available  for  the  years  previous  to  1896.  The  Mineral  Industry  reports  the 
following  averages:  1889,  $25;  1890,  $23-90;  1891,  $25-90;  1892,  $22-50; 
1893,  $19-25;  1894,  $17-10.  The  Mineral  Industry  made  no  quotation  for 
1895 ;  Prof.  Erasmus  Haworth,  State  Geologist  of  Kansas,  gives  the  average 
for  that  year  as  $19-68.  All  of  the  above  figures  refer  to  the  average  grade 
of  ore.  In  this  connection  it  is  important  to  remark  that  the  average  grade 
of  the  ore  produced  in  the  Joplin  district  has  been  increasing,  especially  of 
late  when  the  tendency  has  been  strongly  toward  making  the  cleanest  ore 
possible.  In  the  early  part  of  the  decade,  1890-1900,  the  average  grade  of 
the  ore  produced  in  the  district  was  probably  between  56%  and  58%  Zn;  cer- 
tainly not  more  than  58%.  At  present  the  average  is  probably  very  close  to 
60%,  which  is  rated  as  the  "  standard  "  ore  of  the  district.  A  good  deal  of 
ore  assaying  62%  to  63%  Zn  is  produced,  and  occasionally  lots  assaying  as 
high  as  64-5%.  The  increase  in  the  zinc  tenor  of  the  ore  should  be  borne  in 
mind  in  making  comparisons  between  present  prices  and  those  of  previous 
years.  Unfortunately  ore  was  not  sold  on  an  assay  basis  at  all  previous 
to  1899;  consequently  there  is  uncertainty  as  to  what  the  average  values 
reported  for  earlier  years  really  indicate. 

MISCELLANEOUS  STATISTICS. 

There  are  no  complete  statistics  of  the  production  of  sheet  zinc  in  Europe, 
the  output  being  reported  officially  only  from  Belgium,  Spain  and  Upper 
Silesia.  There  is  scarcely  a  zinc-producing  country  in  Europe,  however, 
which  does  not  have  rolling  mills.  The  statistics  for  Belgium,  Spain  and 
Upper  Silesia  are  presented  in  the  following  table : 


PRODUCTION  OF   SHEET  ZINC   IN   CERTAIN   COUNTRIES. 

(In  metric  tons.) 


Country 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

32  388 

31  724 

34081 

36  238 

37  Oil 

35  587 

34  289 

38  82") 

Silesia  ... 

32  266 

35  187 

34  518 

35  676 

39  488 

36*618 

39  863 

35  646 

38  469 

Spain 

2462 

2  421 

2  487 

2648 

2  337 

1  731 

2  084 

<?  756 

Eeference  has  previously  been  made  to  the  fact  that  the  official  statistics 
of  spelter  production  do  not  include  the  make  of  zinc  dust,  which  is  obtained 


STATISTICS    OF    1'RODIXTIOX    AND   PRICES. 


91 


as  a  by-product  in  smelting  and  is  marketed  in  that  form.  The  output  of 
zinc  dust  in  Belgium  and  Germany  amounts  to  several  thousands  of  tons 
per  annum.  Germany  also  produces  a  considerable  quantity  of  white  vitriol 
(zinc  sulphate)  which  is  obtained  directly  from  ore  and  contains  about 
22-5%  Zn.  The  production  of  zinc  sulphate  in  Germany  is  shown  in  the 
following  table : 

PRODUCTION    OF    ZINC    SULPHATE    IN    GERMANY. 

(In  metric  tons.) 


Year 

Quan- 
tity 

Year 

Quan- 
tity 

Year 

Quan- 
tity 

Year 

Quan- 
tity 

Year 

Quan- 
tity 

Year 

Quan- 
tity 

1871 
1872 
1873 
1874 
1875 

746 
733 
707 
418 
550 

1876 
1877 
1878 
1879 
1880 

685 
443 
327 
511 
812 

1881 
1882 
1883 
1884 
1885 

617 
788 
992 
1,155 
1,130 

1886 
1887 
1888 
1889 
1890 

1,147 
1,268 
1,494 
2,685 
3,769 

1891 
1892 
1893 
1894 
1895 

4,117 
4,479 
4,527 
4,249 
4,018 

1896 
1897 
1898 
1899 
1900 

4,811 
5,488 
6.104 
7,117 
6.026 

Previous  to  1893  a  small  quantity  of  nickel  sulphate  was  included  in  the  statistics  of  production 
of  zinc  sulphate. 

PRODUCTION    OF    SPELTER    IN    UPPER    SILESIA    BY    WORKS. 

(In  metric  tons.) 


Works 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

4,108 
a  1,915 
1.229 
1.291 
2,734 
71 
1,172 
164 
7,108 
5,043 
10.296 
8,016 
1,826 
2,440 
5,585 

Bernhardi 

1  ,065 
1,613 
1,144 
3,120 

935 
146 
7,582 
4,463 
11,774 
3,807 
1,291 
2,524 
6,269 
1,407 
1,061 
7,130 
1,100 
12,660 
12,002 
1,438 
1,659 
10,973 

a'2,595 
1,624 
1,108 
3,312 

940 
142 
7,924 
4,383 
12,112 
3,828 
1,252 
2,402 
6,368 
1,373 
1,426 
7,596 
a 
12,501 
2,619 
1,440 
1,735 
11,733 

212 
ol  ,955 
1,679 
1,179 
3,139 

"  '978 
188 
7,282 
4,092 
11,348 
3,858 
1,453 
2,619 
5,902 
1,278 
1,435 
7,186 
a 
12,520 
12,545 
1,399 
1,627 
11,673 

3,669 
al,860 
1,482 
1,148 
2,986 

1,102 
195 
7.198 
3,945 
10,695 
5,161 
1,556 
2,562 
5,948 
1,173 
1,314 
6,901 

12,960 
12,755 
1,260 
1,663 
11,478 

4,289 
a  1,809 
1,406 
1,342 
2,743 

1,051 
176 
7,323 
4,085 
10,178 
6,319 
1,521 
2,500 
5,896 
143 
1,468 
7,576 

12,887 
12,732 
1,167 
1,634 
11,868 

Beuthener.   ...    .  . 
Carls  
Clara  

852 
1,532 
783 
3,528 

'865 
217 
5,390 
3,181 
11,993 
2.921 
1,010 
2,602 
5,878 
1,198 
1,264 
6,684 
1,112 
12,384 
11,883 
746 
1,361 
11,036 

962 
1,429 
842 
3,440 

'  '  890 
145 
6,341 
4,072 
11,739 
2,864 
968 
2,686 
5,736 
1,249 
1,248 
6,710 
1,209 
12,281 
11,628 
736 
1,384 
10,616 

a2,105 
1,459 
805 
3,416 

'971 
163 
6,991 
4,276 
11,396 
3,429 
979 
2,640 
5,803 
1,183 
1,235 
7,011 

12,370 
11,784 
1.251 
1.396 
10,963 

a2,014 
1,585 
770 
3,175 

"    950 
144 
7,045 
4,250 
11,289 
3,776 
1,065 
2,580 
5,829 
1,301 
1.241 
6,793 

12,180 
12,014 
1,478 
1,421 
11,646 

Fanny  Franz  
Flora 

Franz  
Kgl.  Friedrichs  
Godulla  
Guidotto  

Hohenlohe  
Hugo  
Kunigunde 

Lazy  
Liebehoff  nungs  
Lydognia  
Norma  . 

1,475 
7,496 

12,855 
12,717 
1,177 
1,752 
11,743 

Pauls  
Rosamunde  
Silesia  II 

Silesia  III  

Theresia  . 

Thurzo  
Wilhelmine  

Totals  6 

88,420 

89,175 

91,716'  92  ,546 

93,509 

98,323 

95,547 

99,011 

100,113 

102  213 

a  The  production  of  the  Rosamundehiitte  in  these  years  is  lumped  with  that  of  the  Beuthenerhutte. 

b  In  addition  to  the  spelter  product  there  was  an  output  of  1,093  tons  of  zinc  dust  in  1896 ;  993  in 
1897;  886  in  1898;  915  in  1899,  and  1,472  in  1900.  This  substance  generally  contains  about  90%  Zn.  I* 
is  produced  chiefly  by  the  Godulla,  Guidotto  and  Hohenlohe  works. 

The  statistics  of  the  Societe  Anonyme  de  la  Vieille  Montagne  are  of 
special  interest  inasmuch  as  it  is  the  largest  zinc-producing  company  of 


92 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


the  world.    The  following  table  is  compiled  from  the  annual  official  repoi 
of  that  company : 

STATISTICS    OF    THE    SOCIETE    ANONYME    DE    LA    VIEILLE    MONTAGNE. 

(Capital  stock  9,000,000  francs.) 


Year 

Metric 
tons 
spelter 
produced 

Metric 
tons 
sheet  zinc 
produced 

Metric 
tons 
zinc  white 
produced 

(a)  Average 
price  of 
spelter  — 
\        francs 

Gross  profit  — 
francs 

Dividends 
paid- 
francs 

• 

1894 

54,839 

54,515 

7,669 

1895 

64  497 

57,000 

8,988 

353.26 

2  250  000 

1896 
1897 
1898 
1899 
1900 

68,581 
68,604 
69,351 
69,672 
69,846 

66,893 
68,024 
68,745 
58,369 
66,122 

8,777 
8,357 
8,894 
7,937 
9,111 

402.75 
434.85 
507  .  80 
616.50 
503  .  20 

6,328,726 
6,647,641 
6,953,074 
8,788,639 
5,314,983 

2,925,000 
3,375,000 
4,050,000 
4,612,500 
2,925,000 

a  Average  price  per  metric  ton. 


It  will  be  observed  that  the  combined  production  of  sheet  and  zinc  white  is 
greater  than  the  spelter  product  of  the  company.  This  is  explained  by  the 
fact  that  the  Vieille  Montagne  purchases  spelter  from  other  producers. 


V. 
ANALYSIS  OF  ZINC  ORES  AND'  PRODUCTS. 

In  the  control  of  a  zinc  smeltery  the  most  important. chemical  determina- 
tions that  have  to  be  made  are  for  zinc,  iron,  lead  and  sulphur.  Less 
frequently  it  is  necessary  to  make  analyses  for  cadmium,,  manganese,  lime, 
magnesia  and  silica.  Occasionally  the  chemist  may  be  called  upon  for  an 
analysis  of  the  coal  and  refractory  material  which  are  employed  in  the 
works,  but  the  composition  of  those  substances  having  once  been  satisfac- 
torily determined,  they  are  usually  assumed  to  be  uniform.  At  works  where 
the  coal  supply  has  to  be  purchased,  it  would  be  advantageous  to  make 
frequent  determinations  of  at  least  the  tenor  of  the  coal  in  moisture  and 
ash,  to  furnish  a  guide  in  the  purchase  of  what  is  the  most  important  ma- 
terial consumed  in  the  works,  excepting  ore.  Such  an  investigation  would, 
however,  serve  only  for  the  information  of  the  smelter,  since  there  are 
practically  no  coal  companies  in  the  United  States  at  least  which  will  make 
any  guarantee  as  to  the  quality  of  their  product,  and  the  consumer  is  fre- 
quently compelled  to  content  himself  with  what  is  available,  especially  where 
the  coal  supply  is  necessarily  derived  from  a  particular  and  limited  district. 

DETERMINATION  OF  ZINC. 

There  are  many  methods  for  the  determination  of  zinc,  both  gravimetric 
and  volumetric,  but  in  technical  practice  only  the  volumetric  methods  are 
employed,  they  being  quite  as  accurate  and  much  more  rapid  than  the 
standard  gravimetric  methods.  Consequently  only  the  volumetric  methods 
will  be  described  in  this  chapter,  and  the  chemist  who  is  interested  in  the 
STavimetric  should  refer  to  the  standard  textbooks  of  Fresenius,  Cairns, 
liose  and  others.  There  are  two  methods  of  volumetric  analysis  which  are 
commonly  employed:  (1)  titration  with  a  standardized  solution  of  potas- 
sium ferrocyanide,  and  (2)  titration  with  a  standardized  solution  of  sodium 
sulphide ;  in  Europe  the  sodium  sulphide  method  is  still  generally  in  vogue, 
although  the  potassium  ferrocyanide  titration  is  meeting  with  some  favor. 
The  sodium  sulphide  method  is  cumbersome  and  troublesome  and  decidedly 
inferior  to  the  ferrocyanide  method  in  points  of  accuracy,  simplicity  and 

93 


94  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

speed.  This,  however,  is  simply  a  matter  of  opinion,  as  to  which  chemists 
may  disagree.  Even  in  the  United  States  there  are  some  who  prefer  the 
sodium  sulphide  method  to  the  ferrocyanide. 

POTASSIUM  FERROCYANIDE  METHOD. — This  method  is  based  on  the  fact 
that  zinc  salts  in  an  acid  solution  decompose  potassium  ferrocyanide,  form- 
ing a  white  insoluble  zinc  compound ;  and  that  an  excess  of  the  ferrocyanide 
can  be  detected  by  the  brown  coloration  produced  with  uranium  acetate  or 
nitrate.  Unfortunately  this  method  does  not,  like  many  volumetric  proc- 
esses, lessen  the  necessity  for  a  complete  separation  of  other  metals  which 
appear  in  solution  with  the  zinc,  since  most  metals  give  precipitates  with 
potassium  ferrocyanide  in  zinc  solutions,  but  it  will  give,  with  proper  precau- 
tions, results  which  will  agree  as  closely  with  those  obtained  by  any  of  the 
standard  gravimetric  methods  as  two  gravimetric  determinations  of  the  same 
sample  will  agree  with  each  other,  assuming  that  the  proportion  of  zinc 
in  the  sample  be  not  less  than  ±%.1  H.  van  F.  Furman  expressed  the 
opinion,  based  on  numerous  experiments,  that  once  the  zinc  is  obtained  in 
solution  in  the  proper  form,  its  percentage  may  be  more  safely  determined 
by  this  volumetric  method  than  it  can  be  by  precipitation  and  subsequent 
ignition  and  weighing.2 

To  prepare  the  standard  solution  of  potassium  ferrocyanide,  88  g.  of  the 
chemically  pure  salt 3  are  dissolved  in  2,000  c.c.  of  water.  It  is  best  to 
prepare  the  solution  at  least  one  day  before  standardization.  In  standardiz- 
ing, two  portions  of  0-200  g.  each  of  pure  zinc  oxide,  which  has  previously 
been  ignited  to  convert  any  zinc  carbonate  into  oxide,  are  dissolved  in  10  c.c. 
of  strong,  pure  chlorhydric  acid.  Then  add  7  g.  of  ammonium  chloride 
(which  must  be  chemically  pure)  and  250  c.c.  of  hot  water  and  titrate 
with  the  ferrocyanide.  As  the  end-point  is  neared,  from  time  to  time  a 
drop  of  the  solution  is  removed  on  the  glass  stirring-rod  and  added  to  a 
drop  of  a  solution  of  pure  uranium  acetate  (or  nitrate)  on  a  porcelain 
plate.  So  long  as  there  is  not  an  excess  of  ferrocyanide  in  the  solution, 
the  uranium  acetate  will  retain  its  yellow  color;  but  so  soon  as  the 
ferrocyanide  is  in  slight  excess,  the  uranium  acetate  will  turn  a  light 
brown,  the  shade  being  darker  according  to  the  quantity  of  ferrocyanide  in 
excess.  The  titration  should  be  carried  to  the  point  where  a  slight  brownish 
tint  is  produced  with  the  drop  of  uranium  acetate.  About  16  c.c.  will  be 
required  and  nearly  that  amount  may  be  run  in  before  making  a  test,  but 
the  titration  should  be  finished  carefully  by  testing  after  each  additional 

1  See  Proceedings  of  the  Colorado  Scien-  2  Manual  of  Practical  Assaying,  third  edi- 

tific  Society,  June,  1892;  and  the  Columbia  tion,  p.  205. 

School  of  Mines  Quarterly,  XIV,  i,  40 ;  also  3  This  should  be  tested  especially  to  prove 

ibid.  XXI,  iii,  267  to  272.  the  absence  of  potassium  ferricyanide. 


ANALYSIS   OP   ZINC   ORES   AND   PRODUCTS.  95 

drop  of  ferrocyanide.  As  soon  as  a  brown  tinge  is  obtained  note  the  reading 
of  the  burette  and  then  wait  a  minute  or  two  to  observe  if  one  or  more  of 
the  previous  tests  have  not  also  developed  a  brown  tinge.  Usually  the  end- 
point  will  be  found  to  have  been  passed  by  a  test  or  two,  and  the  proper 
correction  must  then  be  applied  to  the  burette  reading.  A  further  cor- 
rection must  be  made  for  the  quantity  of  ferrocyanide  required  to  produce 
a  brown  tinge  under  the  same  conditions  when  no  zinc  is  present.  In  cal- 
culating the  result,  it  will  be  reckoned  that  200  mg.  of  zinc  oxide  contain 
160-688  mg.  of  zinc;  1  c.c.  of  ferrocyanide  solution  made  up  with  44  g.  per 
liter  will  equal  about  0-01  g.  of  zinc,  or  about  1%  when  1  g.  of  ore  is  taken 
for  assay. 

The  uranium  acetate  solution  is  prepared  by  dissolving  a  sufficient  quan- 
tity of  the  salt  in  water  to  give  a  rather  strong  solution,  which  is  clarified  by 
adding  a  few  drops  of  acetic  acid.  This  solution  should  be  kept  in  a  small 
well-stoppered  bottle  in  a  dark  place,  since  it  is  decomposed  by  the  action  of 
sunlight.  The  solution  of  potassium  ferrocyanide  should  be  kept  in  a 
tightly  stoppered  green  glass  bottle.  This  solution  will  keep  for  a  long 
time  without  alteration,  providing  the  bottle  be  well  stoppered  and  be  not 
exposed  to  strong  sunlight,  but  it  is  advisable  to  restandardize  it  every  two 
or  three  weeks. 

Von  Schulz  and  Low  Process  of  1892. — The  best  method  for  the  technical 
determination  of  zinc  in  ores  was  the  subject  of  a  report  by  a  committee  of 
the  Colorado  Scientific  Society,  which  was  read  at  a  meeting  of  that  society 
June  11,  1892.  That  committee  decided  in  favor  of  a  method  of  determina- 
tion by  titration  with  potassium  ferrocyanide  as  described  by  Messrs,  von 
Schulz  and  Low,  of  Denver,  Colo.,  and  their  method,  or  a  modification  of  it, 
is  now  generally  employed  in  the  United  States.  In  the  method  as  origi- 
nally described  by  von  Schulz  and  Low,  the  ore  is  decomposed  only  by  means 
of  nitric  acid  saturated  with  potassium  chlorate;  this  single  treatment  is 
sufficient  for  most  ores.  In  the  modification  described  by  Furrnan,  1  g.  of 
finely  pulverized  ore  is  digested  in  a  3-5  or  4  in.  casserole  with  15  c.c.  of 
aqua  regia  and  evaporated  nearly  to  dryness.  If  the  ore  be  incom- 
pletely decomposed  by  that  treatment,  which  will  seldom  happen,  how- 
ever, the  solution  must  be  evaporated  to  dryness,  the  silica  dehydrated,  and 
the  insoluble  residue  fused  with  carbonate  and  nitrate  of  soda,  the  fused 
mass  being  then  digested  with  water  and  acid  and  the  silica  separated  in  the 
usual  manner.  In  this  case  the  first  and  second  filtrates  are  combined,  nitric 
acid  is  added,  and  the  solution  is  evaporated  nearly  to  dryness. 

In  either  case  the  subsequent  procedure  is  the  same.  To  the  nearly  dry 
mass  25  c.c.  of  a  saturated  solution  of  potassium  chlorate  in  nitric  acid, 


96  PRODUCTION    AND    PROPERTIES    OF   ZINC. 

prepared  by  shaking  an  excess  of  the  crystals  with  strong,  pure  nitric  acid 
in  a  flask,  is  added  gradually.  The  dish  should  not  be  covered  at  first,  but 
should  be  warmed  gently  until  violent  action  is  ended  and  greenish  fumes 
cease  coming  off.  The  dish  is  then  to  be  covered  with  a  watch  glass  and  its 
contents  boiled  down  to  dryness,  but  overheating  or  baking  is  to  be  avoided ; 
a  drop  of  nitric  acid  adhering  to  the  convex  side  of  the  watch  glass  does 
no  harm.  When  the  preliminary  treatment  with  aqua  regia  is  omitted, 
the  ore  is  digested  directly  with  25  c.c.  of  the  chlorate  solution  in  nitric 
acid,  which  is  evaporated  as  above  described. 

The  dish  is  then  permitted  to  cool  sufficiently  to  be  handled  with  comfort 
and  7  g.  of  ammonium  chloride,  15  c.c.  of  strong  ammonia  water  and 
25  c.c.  of  hot  water  are  added  to  its  contents.  The  latter  are  boiled 
for  one  minute,  the  dish  or  casserole  being  covered  during  that 
operation,  and  are  then  stirred  with  a  rubber-tipped  glass  rod  in 
order  to  insure  that  all  solid  matter  on  the  cover,  sides  and  bottom 
be  either  dissolved  or  disintegrated.  The  contents  of  the  dish  are  next 
filtered  into  a  flask  of  about  250  c.c.  capacity  and  the  insoluble  matter 
remaining  on  the  filter  is  washed  several  times  with  a  hot  solution  of 
ammonium  chloride,  containing  10  g.  of  the  salt  in  1,000  c.c.  of  water.  This 
ammonium  chloride  solution  is  most  conveniently  heated  in  a  wash  bottle; 
it  should  be  boiling  hot  and  made  slightly  alkaline  with  ammonia. 

If  the  addition  of  ammonia  to  the  casserole  has  produced  a  considerable 
precipitate  of  ferric  hydrate,  alumina  hydrate,  etc.,  the  quantity  of  zinc 
hydrate  that  will  be  carried  down  with  it  will  be  too  great  to  be  disre- 
garded, and  it  must  be  recovered  by  redissolving  the  precipitate  and  throw- 
ing it  down  again.1  This  is  done  most  convenient^  and  with  sufficient 
accuracy  for  ordinary  technical  purposes  by  transferring  the  first  pre- 
cipitate from  the  filter  to  the  original  decomposing  vessel,  employing  a 
spatula  and  wash  bottle  for  that  purpose  and  using  as  little  water  as 
possible.  The  excess  of  water  is  evaporated  off  and  the  precipitate  is 
then  treated  with  the  mixture  of  potassium  chlorate  and  nitric  acid  as 
before,  and  subsequently  with  ammonia,  ammonium  chloride  and  hot  water, 
the  original  procedure  being  followed  a  second  time.  The  sec- 
ond precipitate  having  been  filtered  off  and  washed  properly  with  the 
ammonium  chloride  solution,  the  filtrate  is  added  to  that  whicli 

1 E.  Jensch  has  found  that  the  retention  ficed  to  give  a  precipitate  of  Iron  and 
of  zinc  by  the  precipitate  produced  by  alumina  free  from  zinc  in  the  worst  in- 
ammonia  in  the  analysis  of  zinc  ores  is  stances  (Zeits.  f.  angew.  Chem.,  1899,  XX, 
mainly  due  to  the  presence  of  much  alumina  465-467).  The  quick  method  of  re-precipi- 
in  the  ore.  Repeated  re-solution  and  re-  tation  described  above  appears  to  answer, 
precipitation,  however,  effectually  over-  however,  all  the  purposes  of  ordinary  tech- 
come  the  evil.  Four  re-precipitations  suf-  nical  analysis. 


ANALYSIS    OF    ZIXC    ORES    AND   PRODUCTS.  97 

was  first  obtained.  If  the  precipitate  of  ferric  hydrate,  etc.,  obtained 
in  the  first  procedure  be  small,  the  quantity  of  zinc  dragged  down  with  it 
will  be  sufficiently  minute  to  be  ignored  and  the  retreatment  of  the  pre- 
cipitate may  be  omitted.  In  the  case  of  pure  zinc  ores,  such  as  those  of  the 
Joplin  district,  the  percentage  of  iron  is  so  small  that  the  second  treatment 
is  unnecessary. 

In  case  there  is  no  copper  in  the  solution  filtered  off  from  the  precipitate 
of  ferric  hydroxide,  chlorhydric  acid  should  be  added  to  the  point  of  neu- 
tralization, using  a  piece  of  litmus  paper  as  a  guide,  and  then  10  c.c.  in 
excess.  Pains  should  be  taken  to  have  that  degree  of  acidity  in  all  deter- 
minations made  against  the  same  standard.  An  excess  of  chlorhydric  acid 
is  necessary  to  prevent  interference  of  lead,  but  too  great  an  excess  leads  to 
inaccurate  results.  If  the  presence  of  copper  is  manifested  by  a  blue  colora- 
tion of  the  solution,  the  latter  must  be  neutralized  with  chlorhydric  acid 
and  after  addition  of  an  excess,  say  10  c.c.  of  the  acid,  the  copper  must  be 
precipitated  with  sulphureted  hydrogen,  or  by  means  of  aluminum  foil,  thin 
sheet  lead,  or  granulated  lead.  The  last  is  the  most  convenient  and  is 
most  commonly  employed.  From  20  to  40  g.  are  added  to  the  contents  of 
the  flask,  which  should  be  at  a  temperature  of  about  70°  C.,  and  shaken 
vigorously  until  the  copper  in  the  solution  is  precipitated,  after  which  it 
should  be  perfectly  colorless. 

The  solution  which  should  still  be  rather  hot  is  now  ready  for  titration. 
In  performing  the  latter,  it  is  a  good  plan  to  pour  off  about  one-half  of  the 
solution  and  titrate  rapidly  until  the  end-point  is  passed,  thus  discovering 
approximately  the  percentage  of  zinc  in  the  sample.  The  remainder  of  the 
solution  is  then  added  to  the  first  portion  and  the  titration  is  finished 
carefully,  ordinarily  by  additions  of  two  drops  of  ferrocyanide  at  a  time. 
The  addition  of  ferrocyanide  should  be  stopped  at  the  first  appearance  of  a 
brown  color  and  the  reading  of  the  burette  should  be  taken.  This  reading 
is  subject  to  the  same  corrections  as  were  recited  in  connection  with  the 
standardization  of  the  ferrocyanide  solution. 

Gold,  silver,  lead,  copper,  iron,  manganese  and  the  ordinary  constituents 
of  ores  do  not  interfere  with  the  above  scheme.  Cadmium  behaves  like  zinc, 
and  if  it  be  not  removed  by  a  special  process,  the  result  of  the  determina- 
tion will  be  too  high.  When  cadmium  is  known  to  be  present,  it  may  be 
removed,  together  with  the  copper,  by  precipitation  with  sulphureted 
hydrogen,  and  the  titration  for  zinc  may  be  made  upon  the  properly  acidified 
filtrate  without  the  removal  of  the  excess  of  gas.  There  seems  to  be  no 
simpler  way  to  remove  cadmium.  If  the  copper  be  precipitated  either  by 
sulphureted  hydrogen  or  aluminum  foil,  it  may  be  redissolved  in  nitric  acid 


98  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

and  a  rough  determination  of  copper  may  be  made  from  that  solution. 
When  copper  is  present  in  large  quantity  and  is  precipitated  by  sulphureted 
hydrogen,  it  is  likely  to  carry  down  some  zinc  with  it,  except  under  nicely 
drawn  conditions.  Beringer  recommends  therefore  that  in  the  analysis  of 
brass  the  copper  be  precipitated  by  electrolysis  of  a  nitric  acid  solution  be- 
fore proceeding  to  the  titration  of  the  zinc. 

Sulphide  ores  can  ordinarily  be  decomposed  by  a  simple  digestion  with 
the  solution  of  potassium  chlorate  in  nitric  acid.  In  the  case  of  slags 
different  methods  must  be  employed  and  it  appears  to  be  necessary  to  dehy- 
drate the  silica  before  finally  taking  the  zinc  into  solution,  inasmuch  as 
gelatinous  silica  is  likely  to  retain  some  zinc.  Von  Schulz  and  Low  made 
the  following  notes  as  to  details  in  the  process  i1  Acids  destroy  the  delicacy 
of  the  uranium  test  and  for  that  reason  a  strong  aqueous  solution  of  the 
acetate  is  used.  By  having  the  zinc  solution  only  faintly  acid  the  brown 
coloration  in  the  end-test  becomes  almost  instantaneous  and  no  previous 
test  will  develop  a  color.  Under  these  conditions,  however,  lead  is  apt  to 
interfere  seriously  and  the  presence  of  an  excess  of  acid  is  therefore  a 
necessity.  When  a  strong  solution  of  uranium  acetate,  not  acidified,  is 
used  as  indicator,  the  error  caused  by  the  excess  of  acid  in  the  zinc  solution 
amounts  to  only  two  drops  of  ferrocyanide,  which  may  be  allowed  for,  and 
the  brown  tinge  develops  so  rapidly  that  the  end-point  is  seldom  passed  by 
more  than  one  test.  When  an  ore  contains  but  little  copper,  the  granulated 
lead  used  to  precipitate  it  frequently  coheres  in  lumps  that  may  hold  zinc 
solution.  These  lumps  are  most  easily  broken  up  after  a  little  of  the  ferro- 
cyanide has  been  added.  They  appear  to  cause  no  appreciable  error  in 
the  work.  Lead  shot  or  thin  sheet  lead  may  be  used  if  preferred  and  may 
be  cleaned  with  strong  nitric  acid  and  used  repeatedly,  but  it  is  simple  and 
more  satisfactory  to  employ  granulated  lead  and  throw  it  away  after  use. 

The  method  described  above,  although  not  free  from  defects,  has  proved 
well  adapted  for  rapid  and  accurate  work  and  has  been  in  general  use  in 
the  United  States  from  the  time  of  its  first  public  description,  nine  years 
ago ;  no  better  method  has  since  been  offered.  It  is,  of  course,  quite  obvious 
that  the  method  is  not  of  universal  application,  but  must  be  modified  to  suit 
the  particular  conditions.  Sometimes  a  fusion  may  be  necessary  to  effect 
complete  decomposition,  or  perhaps  a  preliminary  treatment  with  chlor- 
hydric  acid  may  be  required,  in  which  case,  however,  all  chlorhydric  acid 
must  be  expelled  before  beginning  the  regular  treatment.  The  operator  is 
expected  to  recognize  such  cases  and  apply  the  remedy.  He  is  cautioned, 
however,  to  be  very  careful  about  modifying  the  method  except  from  actual 

1  Proc.  Colo.  Scientific  Society,  IV,  181. 


ANALYSIS   OF   ZINC    ORES   AND   PRODUCTS.  09 

necessity;  most  of  the  failures  result  either  from  inattention  to  details  or 
the  introduction  of  fancied  improvements. 

Von  Schuh  and  Low  Process  of  1900. — The  latest  form  of  the  von  Schulz 
and  Low  method  was  described  by  A.  H.  Low  in  the  Journal  of  the  American 
Chemical  Society,  XXII,  iv.  198,  April,  1900,  as  follows: 

'"'To  standardize  the  solution  of  potassium  ferrocyanide,  made  up  with 
22  g.  of  the  salt  per  liter,  weigh  carefully  about  100  mg.  of  pure  zinc  and 
dissolve  in  6  c.c.  of  strong  chlorhydric  acid,  using  a  400  c.c.  beaker.  Then 
add  about  10  g.  of  ammonium  chloride  and  200  c.c.  of  boiling  water.  Titrate 
with  the  ferrocyanide  solution  until  a  drop,  when  tested  on  a  porcelain  plate 
with  a  drop  of  a  strong  solution  of  uranium  nitrate,  shows  a  brown  tinge.1 
About  20  c.c.  of  ferrocyanide  will  be  required,  and  accordingly  nearly  that 
quantity  may  be  run  in  rapidly  before  making  a  test,  and  then  the  titration 
should  be  finished  carefully  by  testing  after  each  additional  drop.  Instead  of 
using  a  single  drop  of  the  zinc  solution  for  the  test,  the  reaction  is  much 
sharper  if  several  drops  are  placed  in  a  depression  of  the  plate  and  tested 
with  a  single  drop  of  a  strong  uranium  solution.  As  this  is  near  the  end  of 
the  titration  the  quantity  of  zinc  lost  thereby  is  insignificant.  As  soon  as 
a  brown  tinge  is  obtained,  note  the  reading  of  the  burette  and  then  wait  a 
minute  or  two  and  observe  if  one  or  more  of  the  preceding  tests  do  not  also 
develop  a  tinge.  The  end-point  is  usually  passed  by  a  test  or  two  and  the 
burette  reading  must  be  corrected  accordingly.  A  further  correction  must 
be  made  for  the  quantity  of  ferrocyanide  required  to  produce  a  tinge  under 
the  same  conditions  when  no  zinc  is  present.  This  is  only  one  or  two  drops. 
One  cubic  centimeter  of  the  standard  solution  will  equal  about  0-005  g.  of 
zinc,  or  about  1%  when  0-5  g.  of  ore  is  taken  for  assay. 

"To  0-5  g.  of  ore  in  a  250  c.c.  pear-shaped  flask,  add  about  2  g.  of 
potassium  nitrate  and  5  c.c.  of  strong  nitric  acid.  Heat  until  the  acid  is 
about  half  gone  and  then  add  10  c.c.  of  a  cold  saturated  solution  of 
potassium  chlorate  in  strong  nitric  acid  and  boil  to  complete  dryness.  It  is 
usually  necessary  to  manipulate  the  flask  in  a  holder  over  a  naked  flame  to 
avoid  loss  by  bumping.  The  boiling  may  be  conducted  rapidly,  and  toward 
the  end  it  is  best  to  heat  the  entire  flask  so  as  to  expel  every  trace  of  liquid. 
The  potassium  nitrate  serves  simply  as  a  diluent  of  the  dry  residue  and 

Observe  that  Mr.  Low  now  recommends  March  18,   1901,  stated  that  he  had  found 

the  use  of  uranium  nitrate  instead  of  ura-  uranium   acetate   to  be   an   unreliable   indl- 

nium  acetate  as  indicator.     Other  chemists  cator  in  the  presence  of  small  quantities  of 

agree  with  him  in  that  respect.  A.  C.  Lang-  chlorhydric   acid ;    uranium   nitrate   in    thu 

muir  in  a  paper  read  before  the  New  York  form  of  a  3%  or  4%  solution  is  much  more 

Section  of  the  American  Chemical   Society,  satisfactory. 


100  PRODUCTION   AND   PROPERTIES    OF   ZINC. 

insures  the  completeness  of  the  subsequent  extraction  of  the  zinc.  Cool  suf- 
ficiently and  add  30  c.c.  of  a  prepared  ammoniacal  solution  and  heat  to 
boiling.  This  solution  is  made  by  dissolving  200  g.  of  ammonium  chloride 
in  a  mixture  of  500  c.c.  of  strong  ammonia  water  and  350  c.c.  of  water.  Boil 
the  contents  of  the  flask  very  gently  for  about  two  minutes  and  then  filter 
through  a  9  cm.  paper  and  wash  with  a  hot  solution  of  ammonium  chloride 
containing  about  100  g.  of  the  salt  and  50  c.c.  of  strong  ammonia  water  to 
the  liter.  Collect  the  filtrate  in  a  400  c.c.  beaker.  The  insoluble  residue 
should  be  completely  disintegrated  and  any  ferric  hydroxide  present  should 
appear  of  a  fine  sandy  nature.  Place  a  bit  of  litmus  paper  in  the  filtrate 
(not  necessary  if  much  copper  is  present)  and  neutralize  carefully  with 
chlorhydric  acid,  finally  adding  6  c.c.  of  the  strong  acid  in  excess.  Dilute 
to  about  150  c.c.  and  add  50  c.c.  of  a  cold  saturated  solution  of  hydrogen 
sulphide.  Heat  nearly  to  boiling  and  the  solution  is  ready  for  titration.  If 
more  convenient,  or  apparently  advisable,  pass  a  current  of  hydrogen  sul- 
phide gas  through  the  hot  solution  diluted  to  200  c.c.  Copper  and  cadmium, 
which  are  interfering  metals,  are  thus  precipitated.  Unless  in  large  amount 
they  need  not  be  filtered  off.  Practically  no  zinc  is  precipitated  with  the 
copper  under  these  conditions  and  the  discoloration  of  the  liquid  by  even 
10%  of  copper  does  not  badly  mask  the  uranium  test. 

"  Titrate  the  hot  solution  as  follows :  Pour  off  about  one-third  and  set  it 
aside  in  a  beaker.  Titrate  the  remainder  more  or  less  rapidly,  according 
as  much  or  little  zinc  is  indicated,  until  the  end-point  is  passed,  using  the 
uranium  indicator  as  in  the  standardization.  Then  add  the  greater  part  of 
the  reserved  portion  and  continue  the  titration  with  more  caution  until  the 
end-point  is  again  passed.  Finally  add  the  last  of  the  reserved  portion  and 
finish  the  titration  carefully,  ordinarily  two  drops  at  a  time.  Make  cor- 
rections of  the  final  reading  of  the  burette  precisely  as  in  the  standardiza- 
tion. The  true  end-point  is  always  slightly  passed,  and,  after  waiting  a 
minute,  it  is  usually  sufficient  to  deduct  for  as  many  drops  as  show  a  brown 
tinge  and  one  test  additional. 

"When  precipitating  with  hydrogen  sulphide  it  is  a  matter  of  considerabl 
importance  to  have  the  solution  of  a  definite  degree  of  acidity.    Cadmiui 
and  copper  are  to  be  precipitated,  while  it  is  better  to  retain  lead  in  solutioi 
and  not  unnecessarily  blacken  the  liquid  with  its  sulphide.     If  there 
enough  acid  to  prevent  the  precipitation  of  its  sulphide  the  lead  will  nol 
interfere  in  the  titration.     On  the  other  hand  too  much  acid  will  prevent 
the  precipitation  of  the  cadmium.    It  will  not  come  down  from  a  boilin< 
hot  solution  containing  5%  of  strong  chlorhydric  acid,  but  it  is  readily  prc 
cipitated  from  a  %%  solution,  while  lead  is  not,  if  the  liquid  be  nearly 


ANALYSIS   OF   ZINC   ORES   AND   PRODUCTS.  101 

boiling.  It  is  therefore  recommended  to  have  an  excess  of  6  c.c.  of  strong 
chlorhydric  acid  in  the  final  bulk  of  200  c.c.  of  solution. 

"Arsenic,  when  present  in  large  amount,  sometimes  makes  trouble  by 
retaining  iron  in  the  ammoniacal  solution.  No  attention  need  be  paid  to- 
arsenic  unless  its  presence  in  excess  is  thus  indicated.  In  such  a  case  begin 
anew  and  give  the  ore  a  preliminary  treatment  as  follows:  To  0-5  g.  of 
ore  in  the  flask  add  10  c.c.  of  strong  chlorhydric  acid  and  1  c.c.  of  bromine. 
Warm  very  gently  for  several  minutes  to  decompose  the  ore  without  loss  of 
bromine  and  then  boil  rapidly  to  complete  dryness.  The  arsenic  will  thus 
be  sufficiently  expelled.  Then  add  the  potassium  nitrate  and  nitric  acid  and 
proceed  in  the  usual  manner. 

"  In  the  case  of  ores  that  are  free  from  cadmium,  or  where  cadmium  may 
be  neglected,  the  copper  may  be  readily  precipitated  without  the  use  of 
hydrogen  sulphide  as  follows:  after  neutralizing  the  ammoniacal  filtrate 
from  the  insoluble  residue,  acidify  with  an  excess  of  10  c.c.  of  chlorhydric 
acid  and  add  about  30  g.  of  granulated  test  lead.  Heat  nearly  to  boiling 
and  stir  the  lead  about  until  all  the  copper  is  precipitated.  Then  dilute  to 
200  c.c.  and  titrate  as  described,  without  removing  the  lead  and  precipitated 
copper." 

Stone's  Process  for  the  Analysis  of  Manganiferous  Zinc  Ore. — G.  C.  Stone 
described  a  modification  of  the  original  von  Schulz  and  Low  method,  which 
presents  advantages  in  the  analysis  of  manganiferous  zinc  ores,  like  those 
of  New  Jersey.1  According  to  his  method,  sulphide  ores  are  best  dissolved 
in  chlorhydric  acid  and  potassium  chlorate,  care  being  taken  to  have  suf- 
ficient acid  present  to  insure  keeping  all  the  manganese  in  solution.  Oxides,, 
carbonates  and  silicates  are  dissolved  in  chlorhydric  acid  and  boiled  with 
the  addition  of  potassium  chlorate.  Ores  containing  franklinite  or  rhodonite 
must  first  be  fused  with  sodium  carbonate  and  evaporated  to  dryness  with 
chlorhydric  acid  to  insure  thorough  decomposition,  being  then  redis- 
solved  with  chlorhydric  acid  in  slight  excess  and  boiled  with  potassium 
chlorate  to  oxidize  the  iron.  Iron  and  alumina  are  precipitated  with  a 
solution  of  barium  carbonate,  which  is  prepared  by  warming  the  pure  salt 
suspended  in  water  with  2%  or  3%  of  its  weight  of  barium  chloride;  this 
converts  the  alkaline  carbonate  present  into  chloride,  while  the  barium 
chloride  remaining  in  the  solution  does  not  interfere  with  the  process.  The 
barium  carbonate  must  be  free  from  ammonia,  and  in  effecting  the  solution 
it  should  be  warmed  for  several  hours.  The  solution  from  which  the  iron 
and  alumina  are  precipitated  should  not  contain  a  large  quantity  of  free 
acid.  The  iron  must  all  be  in  the  ferric  state. 

1  Journal  of  the  American  Chemical  Society,  XVII,  473,  June,  1895. 


102  PRODUCTION   AND   PROP^JITIES   OF   ZINC. 

The  thoroughly  oxidized  solution  of  the  ore  is  washed  into  a  500  c.c.  flask, 
cooled,  and  barium  carbonate  suspended  in  water  is  added  until  the  pre- 
cipitate curdles,  an  excess  doing  no  harm.  The  precipitate  is  then  filtered 
off  and  the  solution  is  made  up  to  500  c.c.  The  solution  should  be  filtered 
from  the  iron  immediately,  in  order  to  avoid  precipitation  of  zinc,  and 
should  be  titrated  as  soon  as  filtered;  if  it  be  necessary  to  let  the  solution 
stand  it  must  be  made  slightly  acid,  else  some  zinc  will  precipitate.  Aliquot 
portions  are  taken  for  titration.  One  portion,  which  should  contain  be- 
tween 0-01  and  0-04  g.  of  manganese,  is  diluted  to  about  200  e.c.,  heated 
nearly  to  boiling  in  a  white  porcelain  dish,  and  titrated  rapidly  with  the 
standard  potassium  permanganate  solution,  with  very  vigorous  stirring. 
The  greater  part  of  the  permanganate  necessary  should  be  added  rapidly,  or 
the  manganese  oxide  is  apt  to  stick  to  the  sides  of  the  dish,  making  it  diffi- 
cult to  see  the  pink  color  of  the  solution  at  the  end;  therefore  if  the  per- 
centage of  manganese  in  the  sample  be  not  approximately  known  it  is  best 
to  make  a  rough  preliminary  titration,  running  in  1  or  2  c.c.  at  a  time.  In 
a  second  portion,  made  slightly  acid  with  chlorhydric,  the  zinc  and  man- 
ganese are  titrated  together  by  standard  potassium  ferrocyanide  solution. 
Inasmuch  as  manganous  ferrocyanide  is  soluble  in  a  large  excess  of  chlor- 
hydric  acid,  a  large  quantity  of  the  latter  is  to  be  avoided,  but  5  c.c.  added  to 
100  c.c.  of  the  solution  do  not  cause  any  appreciable  error.  The  solu- 
tion is  titrated  cold.  If  manganese  be  present  in  appreciable  quantity  the 
color  of  the  precipitate  will  darken  as  the  ferrocyanide  is  run  in  and  sud- 
denly change  to  a  light  greenish  yellow  shortly  before  the  end  is  reached. 
If  lead  be  present  in  the  solution,  it  must  be  sufficiently  acid  to  prevent 
precipitation  of  that  element  by  the  ferrocyanide.  A  proportion  of  5  c.c. 
of  chlorhydric  acid  in  100  c.c.  of  solution  is  sufficient  to  prevent  that  and 
is  not  so  much  as  to  cause  any  appreciable  error  on  account  of  the  solubility 
of  manganous  ferrocyanide.  A  dilute  solution  of  cobalt  nitrate  is  em- 
ployed as  indicator.  A  drop  of  the  cobalt  solution  is  placed  on  a  white 
porcelain  plate  and  a  drop  of  the  solution  to  be  tested  is  added  so  that  the 
drops  touch,  but  do  not  mix ;  a  faint  greenish  line  immediately  shown  at 
the  junction  of  the  drops  marks  the  end  reaction.  The  solution  should 
not  be  warmer  than  the  ordinary  temperature  of  the  laboratory. 

The  manganese  is  precipitated  as  Mn.{Fe2(CN")12,  wherefore  a  quantity  of 
potassium  ferrocyanide  that  will  precipitate  four  atoms  of  zinc  will  pre- 
cipitate only  three  atoms  of  manganese.  The  calculation  of  results  is 
illustrated  by  the  following  example :  "  The  strength  of  the  f errocyanide 
solution  was  1  c.c.=0-00606  g.  zinc=0-00384  g.  manganese.  The  strength 
of  the  permanganate  solution  was  1  c.c.=0-001  g.  manganese:  2-5  g.  of  ore 


ANALYSIS    OF    ZIXC    ORES    AXD    PRODUCTS.  103 

were  dissolved  and  the  solution  was  diluted  to  500  c.c. ;  50  c.c.  of  this  solution 
were  taken  for  the  determination  of  manganese  and  100  c.c.  for  the  determi- 
nation of  zinc.  Inasmuch  as  1845  c.c.  (—7-38%  Mn)  were  used  in  the  first 
and  27*85  c.c.  were  used  in  the  second  titration,  it  is  necessary  to  deduct  9*61 
c.c.  (for  the  0-0369  g.  of  manganese  present  in  the  100  c.c.)  from  27-85  c.c., 
leaving  18-24  c.c.  for  the  zinc,  equal  to  0-11053  g.,  or  22-11%  Zn." 

This  method  has  been  used  with  very  satisfactory  results  in  the  labora- 
tories of  the  New  Jersey  Zinc  Company,  the  determinations  of  both  zinc 
and  manganese  by  it  agreeing  closely  with  those  by  gravimetric  methods. 
In  titrating  manganese  with  potassium  ferrocyanide  solution,  the  uranium 
salts  cannot  be  used  as  indicators  because  they  react  on  the  precipitated 
manganese  ferrocyanide.  Cobalt  nitrate  was  found  to  be  the  best  indicator. 
The  solution  of  it  should  be  dilute.  In  making  the  tests  on  the  porcelain 
plate  care  should  be  taken  that  the  drops  do  not  mix,  which  would  make  it 
impossible  to  observe  the  reaction.  If  the  color  at  the  junction  of  the 
drops  does  not  show  at  once,  the  end-point  is  not  reached.  Often  when  near 
the  end  it  will  show  after  standing  a  few  seconds,  but  at  the  actual  end- 
point  it  shows  as  soon  as  the  drops  touch.  The  ferrocyanide  solution  is 
best  made  up  with  about  30  g.  per  1,000  c.c.  It  is  standardized  by  titrating 
solutions  containing  about  0-1  g.  of  zinc,  made  slightly  acid  with  chlorhy- 
dric,  and  kept  at  about  the  same  volume  as  is  used  in  the  analysis.  The 
quantity  of  ferrocyanide  necessary  to  give  a  reaction  with  cobalt  in  this 
volume  of  acidulated  water  must  be  determined,  and  the  amount  so  found 
deducted  for  each  titration;  it  is  about  0-7  c.c.  for  a  volume  of  140  c.c. 
The  solution  of  potassium  permanganate  is  made  up  with  1-99  g.  per  1,000 
c.c.,  which  makes  1  c.c.=0-001  g.  of  manganese.  It  is  standardized  against 
iron  in  the  usual  manner,  the  manganese  equivalent  being  found  by  multi- 
plying the  iron  value  by  0-294646. 

Additional  Notes  Respecting  the  Ferrocyanide  Method. — Among  the  other 
precautions  to  be  observed  in  executing  the  ferrocyanide  assay  for  zinc  are 
to  have  approximately  the  same  bulk  of  solution  in  all  the  titrations;  to 
have  the  same  quantity  of  HC1  present;  and  to  perform  the  titration  at 
about  the  same  temperature.  If  there  be  too  large  an  excess  of  acid,  or  if 
the  solution  be  too  hot,  a  decomposition  is  likely  to  take  place,  resulting  in 
the  liberation  of  chlorine,  which  may  be  known  by  the  solution  becoming 
yellow  or  yellowish  green.  On  the  other  hand,  cold  solutions  should  not  be 
titrated ;  they  give  results  that  are  too  high.  In  a  well-done  assay  the  pre- 
cipitate should  always  be  white  and  the  solution  colorless  or  nearly  so. 
The  bluish  color  which  the  precipitate  frequently  manifests  is  due  to  the 
presence  of  traces  of  iron. 


104  PRODUCTION    AND   PROPERTIES   OF    ZINC. 

L.  L.  de  Koninck  and  Eugene  Prost,  after  an  elaborate  investigation  of  the 
volumetric  determination  of  zinc  by  potassium  ferrocyanide,  came  to  the 
conclusion  that  the  reaction  is  more  regular  and  its  termination  more 
sharply  marked  if  the  ferrocyanide  is  always  in  excess  with  respect  to  zinc — 
e.g.,  if  the  zinc  solution  should  be  run  into  the  ferrocyanide.  This  involves 
inverse  titration,  which  is  not  very  practicable,  or  else  to  titrate  back.  The 
latter  method  has  the  advantage  of  showing  the  approaching  termination 
of  the  reaction  by  the  diminution  of  the  intensity  of  color  produced  by  the 
indicator ;  for  these  reasons  de  Koninck  and  Prost  give  preference  to  it.1 

E.  H.  Miller  and  E.  J.  Hall  investigated  the  influence  of  various  sub- 
stances likely  to  be  present  when  zinc  is  estimated  by  titration  with  potas- 
sium ferrocyanide  and  uranium  acetate  is  used  as  indicator,  such  substances 
being  added  in  successively  increased  quantity  to  constant  known  amounts  of 
zinc  solution  which  were  titrated  with  ferrocyanide  of  a  definite  strength, 
uniform  conditions  of  temperature  and  volume  being  carefully  maintained. 
The  following  conclusions  were  drawn:  (1)  Salts,  such  as  calcium  chloride 
and  sodium  citrate,  and  acids,  especially  chlorhydric,  disturb  the  end  re- 
action by  their  solvent  effect  on  uranium  ferrocyanide.  (2)  Zinc  ferro- 
cyanide diminishes  this  effect  in  the  case  of  chlorhydric  acid ;  the  correction 
established  from  blank  tests  is  therefore  slightly  too  great.  (3)  Ammonium 
chloride,  not  exceeding  17  parts,  c*oes  not  affect  the  accuracy  of  the  method, 
but  has  some  unknown  action  on  zinc  ferrocyanide.  (4)  Aluminum  sul- 
phate, in  considerable  quantity,  renders  the  results  unreliable.  (5)  Twelve 
parts  of  concentrated  chlorhydric  acid,  sp.  g.  1-2,  suffice  to  prevent  inter- 
ference by  lead.  (6)  Antimony  gives  high  results,  but  small  quantities  of 
bismuth  have  no  influence.2 

SODIUM  SULPHIDE  METHOD. — In  the  technical  laboratories  of  Belgium, 
France,  Germany,  Sardinia  and  Spain  the  determination  of  zinc  in  ores  and 
furnace  products  is  commonly  made  by  titration  with  a  standardized  solu- 
tion of  sodium  sulphide,  the  methods  employed  being  more  or  less  modifica- 
tions of  that  which  is  known  by  the  name  of  Schaffner.  In  the  United 
States  sodium  sulphide  titration  is  employed  by  a  comparatively  few 
chemists,  who  prefer  it  to  the  ferrocyanide  method. 

The  estimation  of  zinc  by  titration  with  sodium  sulphide  depends  upon 
the  power  of  that  reagent  to  throw  down  a  white  precipitate  of  zinc  sul- 
phide from  an  ammoniacal  solution.  Various  indicators  are  employed  to 
show  when  the  zinc  has  been  entirely  precipitated  and  sodium  sulphide  is 
in  excess.  A  solution  of  ferric  chloride  is  frequently  employed.  Upon  its 

*  Chemical  News,  July  9  and  16, 1897. 

«  Columbia  School  of  Mines  Quarterly,  1900,  XXI,  iii,  267-272. 


ANALYSIS    OF    ZINC    OKES    AND    PRODUCTS.  1<)5 

addition  to  the  ammoniacal  solution  of  zinc,  flakes  of  ferric  hydrate  are 
produced,  which  retain  their  color  until  all  the  zinc  has  been  precipitated, 
but  blacken  immediately  in  the  presence  of  an  excess  of  sodium  sulphide. 
Instead  of  ferric  chloride,  solutions  of  nickel  sulphate  or  lead  acetate 
may  be  used,  drops  of  those  solutions  being  tested  on  a  porcelain  plate  in  the 
usual  manner;  an  excess  of  sodium  sulphide  causes  a  black  precipitate  to 
be  formed.  Acetate  of  lead  paper  is  also  sometimes  employed. 

The  solution  of  ferric  chloride  is  prepared  by  dissolving  3  g.  of  iron  wire 
in  chlorhydric  acid  and  a  little  nitric  acid  and  diluting  to  one  liter.  The 
sodium  sulphide  solution  is  prepared  by  dissolving  about  100  g.  of  crystal- 
lized sodium  sulphide  in  2,500  c.c.  of  water.  The  solution  should  be  filtered 
or  decanted  in  order  to  remove  any  black  precipitate  which  may  be  formed 
in  small  quantity. 

The  sodium  sulphide  solution  is  standardized  against  metallic  zinc  or  zinc 
oxide  dissolved  in  chlorhydric  acid  containing  a  small  quantity  of  nitric  acid. 
The  solution  of  zinc  is  diluted,  in  a  flask,  to  about  500  c.c.  and  ammonia 
in  excess  is  added,  after  which  5  c.c.  of  the  ferric  chloride  solution  is 
introduced.  The  solution  of  sodium  sulphide  is  then  run  slowly  from  a 
burette  into  the  cold  ammoniacal  solution,  which  should  be  agitated  con- 
tinuously, until  the  ferric  hydrate  is  blackened. 

In  determining  the  zinc  in  ore,  from  0-5  to  1  g.  is  weighed  up  and  heated 
with  chlorhydric  acid  and  a  little  nitric  acid,  a  large  excess  of  acid  being 
avoided.  When  decomposition  is  completed,  the  solution  is  diluted  and 
ammonia  and  ammonium  carbonate  are  added  in  excess.  The  solution  is 
then  heated  gently  for  about  20  minutes,  filtered  into  a  flask  and  the  residue 
on  the  filter  well  washed  with  hot  ammoniacal  water.  To  5  c.c.  of  the  ferric 
chloride  solution  ammonia  is  added  in  sufficient  quantity  to  precipitate  the 
iron,  after  which  the  whole  is  poured  into  the  ammoniacal  zinc  solution; 
this  procedure  prevents  the  coagulation  which  would  be  likely  to  occur  if  the 
ferric  chloride  were  added  directly.  When  the  solution  is  cold,  the  titration 
with  sodium  sulphide  is  performed,  observing  the  precaution  to  keep  the 
contents  of  the  flask  in  continuous  agitation. 

When  iron  is  present  in  the  ore  in  only  a  small  quantity  the  assay  may 
be  made  without  filtering  off  the  hydroxide  which  is  precipitated  upon 
addition  of  the  ammonia,  but  it  is  preferable  to  remove  it  and  it  is  essential 
to  do  so  if  the  quantity  is  considerable,  since  the  precipitated  ferric  hydrate 
is  likely  to  retain  zinc  oxide;  in  the  latter  case  the  precipitate  should  be 
redissolved  and  reprecipitated,  the  second  solution  being  added  to  the  first. 
If  manganese  is  present  in  the  ore  complete  precipitation  is  insured  by  the 
addition  of  a  few  drops  of  bromine  water  to  the  ammoniacal  solution.  If 


106  PRODUCTION    AXD    PUOPEHTILS    OF    ZINC. 

the  presence  of  copper  is  manifested  by  the  blue  coloration  of  the  solution, 
that  metal  must  be  removed  by  one  of  the  conventional  methods.  If  silver 
is  present  in  sufficient  quantity  to  vitiate  the  result  it  should  be  separated 
by  filtration  from  the  chlorhydric  acid  solution,  before  addition  of  the 
ammonia.  Lead  and  cadmium  do  not  interfere  with  the  accuracy  of  the 
sodium  sulphide  assay ;  the  former  remains  insoluble  as  sulphate  or  if  taken 
into  solution  is  precipitated  by  the  ammonium  carbonate,  while  cadmium 
is  insoluble  in  the  ammoniacal  solution.  This  is  an  advantage  of  the 
sodium  sulphide  method  over  the  ferrocyanide  in  the  case  of  ores  which 
contain  cadmium,  inasmuch  as  the  special  procedure  for  the  elimination 
of  the  cadmium  is  unnecessary. 

Another  method  of  sodium  sulphide  titration  was  described  by  H.  Nissen- 
son  and  B.  Neumann  in  Chemiker  Zeitung,  XIX,  1624,  and  the  Journal 
of  the  Society  of  Chemical  Industry,  Jan.  31,  1896,  p.  52.  The  follow- 
ing is  an  abstract  of  their  paper : 

"  In  the  Schaffner  process,  the  titration  is  made  in  an  ammoniacal 
solution,  and  the  indicator  may  be  ferric  hydroxide  suspended  in  the  solu- 
tion, or  ferric  chloride  (Streng),  nickel  chloride  (Kiinzel),  cobalt  chloride 
(Deus),  alkaline  lead  tartrate  (F.  Mohr),  lead  acetate  (Fresenius),  sodium 
nitroprusside  (C.  Mohr),  thallium  nitrate  (Schroder),  or  lead  carbonate 
(Schott).  But  of  all  these,  only  the  first  (freshly  precipitated  ferric 
hydroxide)  and  the  last  are  generally  used.  In  the  analysis  of  blende,  1  g. 
of  the  ore  (or  0-5  g.,  if  it  contain  more  than  25%  Zn)  is  heated  in  a 
flask  with  12  c.c.  of  strong  chlorhydric  acid,  until  all  hydrogen  sulphide  has 
been  driven  off;  the  solution  is  then  peroxidized  with  3  c.c.  of  nitric  acid, 
and  after  a  short  time  7  c.c.  of  sulphuric  acid  (1:2)  are  added,  and  the 
whole  is  evaporated  until  sulphuric  acid  fumes  are  observed.  After  cooling, 
the  liquid  is  diluted  and  filtered.  If  cupriferous,  the  solution  is  boiled 
before  filtration  with  5  to  7  c.c.  of  sodium  thiosulphate  solution  (1:  10) 
until  no  more  smell  of  sulphur  dioxide  can  be  detected.  The  precipitate 
which  contains  the  silica,  lead,  and  copper  is  filtered  off,  and  the  filtrate  is 
peroxidized  with  bromine  water,  and  then  treated  with  25  c.c.  of  ammonia 
(sp.  gr.  0-925)  for  the  separation  of  iron,  manganese  and  alumina.  After 
boiling  and  filtering,  the  precipitate  is  redissolved  in  chlorhydric  acid  (or  in 
aqua  regia,  if  highly  manganiferous)  and  again  precipitated. 

"  The  mixed  filtrates  are  made  up  to  500  c.c.  and  set  aside  for  12  to  18 
hours  for  the  removal  of  the  great  excess  of  ammonia.  Simultaneously,  a 
quantity  of  pure  zinc,  approximately  equal  to  that  in  the  ore  under  deter- 
mination, is  weighed  accurately,  dissolved  in  a  similar  quantity  of  chlor- 
hydric and  nitric  acids,  mixed  with  25  c.c.  of  ammonia,  made  up  to  500  c.c. 


ANALYSIS    OF   ZINC    ORES   AND   PRODUCTS.  107 

and  set  aside.  Coda  has  shown  that,  to  insure  accuracy,  it  is  not  neces- 
sary to  employ  sulphuric  acid  for  the  solution  of  the  check  zinc. 

"A  shorter  method,  employed  by  the  authors,  consists  in  taking  double 
the  quantities  above  quoted  all  through,  dissolving  and  proceeding  as  above, 
but  boiling  with  sulphuric  acid  only  for  five  or  ten  minutes  (not  to  dryness) 
until  red  fumes  cease  to  be  evolved,  making  up  to  50Q  c.c.  after  adding  the 
ammonia,  and  filtering  off  only  250  c.c.,  which  is  then  made  up  again  to 
500  c.c.  for  titration.  The  result  may  be  a  little  low,  but  the  error  does  not 
exceed  0-1%,  while  the  titration  is  better  effected,  owing  to  the  absence  of 
great  excess  of  ammonia. 

"  The  success  of  the  whole  process  depends  upon  attention  to  details  in 
the  titration.  The  sodium  sulphide  solution  should  contain  35  g.  of  the 
crystallized  salt  per  liter,  which  is  equivalent  to  about  0-01  g.  Zn  per  cubic 
centimeter,  but  the  titer  rapidly  alters  on  exposure  to  air,  which  necessitates 
the  simultaneous  performance  of  a  check  test  with  pure  zinc.  The  burette 
may  with  advantage  have  a  side-tube  directly  connected  with  the  bottle  con- 
taining the  stock  of  standard  solution,  in  order  to  minimize  the  action  of 
the  air  when  the  burette  is  filled.  Care  must  be  taken  that  the  color  of  the 
spot  upon  the  lead  paper,  which  marks  the  end  of  the  reaction,  shall  be 
identical  in  the  ore-  and  check-solutions,  as  in  that  case  the  variation  in 
the  sensitiveness  of  the  eyes  of  certain  operators  in  regard  to  the  detection  of 
the  first  darkening  of  the  paper  is  eliminated.  Two  drops  should  be 
allowed  to  fall  successively,  after  the  lapse  of  a  few  seconds,  upon  the 
same  spot  upon  the  paper,  the  drops  being  taken  from  the  solution  by  means 
of  a  narrow  glass  tube,  which  also  serves  as  a  stirrer.  Toward  the  end  of 
the  operation,  a  test  should  be  made  after  each  fresh  addition  of  0-1  c.c.  and 
very  thorough  stirring  must  be  effected  each  time.  A  high  temperature 
(even  that  of  a  hot  summer  day)  and  a  great  excess  of  ammonia  alike 
interfere  with  the  sharpness  of  the  spotting  reaction.  The  titration  must, 
of  course,  be  made  in  a  room  of  which  the  air  is  quite  free  from  hydrogen 
sulphide. 

"  When  copper  is  present  it  is  possible  to  make  a  determination  in  the 
above  way  on  a  part  of  the  solution,  deducting  from  the  result  the  equivalent 
of  copper  found  colorimetrically  in  another  portion ;  but  this  is  not  recom- 
mended, as  the  presence  of  copper  sulphide  interferes  with  the  sharpness 
of  the  lead-paper  indications.  For  approximate  and  rapid  work  with 
cupriferous  smelting  products,  the  separation  of  copper  may  be  avoided  by 
adding  to  the  ammoniacal  solution,  before  titration,  sufficient  potassium 
cyanide  solution  to  remove  all  but  a  trace  of  the  blue  color  from  the  liquid. 
A  trace  of  blue  is  left  to  insure  that  no  excess  of  cvanide  shall  have  been 


108  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

added,,  as  this  would  interfere  with  the  accuracy  of  the  result,  through  the 
formation  of  a  double  cyanide  of  zinc. 

"  The  sodium  sulphide  method  if  properly  conducted  will  give  results  in 
exact  concordance  with  those  obtained  gravimetrically." 

H.  Pellet  found  that  the  ammoniacal  salts,  produced  when  ammonia  is 
employed  in  the  estimation  of  zinc  in  plumbiferous  minerals  by  the  Schaff- 
ner  method  to  neutralize  the  acid  solution  before  titrating  the  zinc  with 
sodium  sulphide,  retain  in  solution  the  lead  present  and  so  falsify  the 
titration.1  In  order  to  avoid  such  error  he  substituted  potash  in  that 
operation,  leaving  the  liquid  just  sufficiently  acid  to  prevent  the  deposition 
of  the  zinc.  The  solution  is  then  poured  into  ammonia,  agitated,  and 
filtered,  the  filtrate  being  titrated  with  standardized  sodium  sulphide,  one 
drop  of  ferric  chloride  (20%)  solution  being  added  as  indicator.  By  this 
means  the  method  retains  its  accuracy  even  in  presence  of  40%  of  lead.  It 
is  found  that  the  volume  of  sodium  sulphide  solution  required  per  unit  of 
zinc  increases  slightly  with  the  dilution  of  the  liquid.  An  important  point 
is  to  pour  the  neutralized  solution  into  the  ammonia,  and  thereby  obviate 
the  deposition  of  zinc  oxide,  which  would  otherwise  have  to  be  redissolved. 
In  dissolving  the  mineral,  Pellet  prefers  to  oxidize  the  iron  present  by 
means  of  potassium  chlorate  instead  of  nitric  acid. 

E.  G.  Ballard  recommends  the  use  of  a  bright  silver  plate  for  determining 
the  end-point  in  the  titration  of  zinc  with  sodium  sulphide  solution.  If  the 
titration  is  done  with  a  cold  solution,  a  large  excess  of  ammonia  is  to  be 
avoided.2  c 

OTHER  METHODS. — For  a  description  of  other  volumetric  methods  and 
the  standard  gravimetric  methods  the  reader  is  referred  to  the  various  text- 
books of  analytical  chemistry.  Some  notes  from  recent  chemical  literature 
are  subjoined. 

Titration  with  Standard  Acid. — Dementief  has  proposed  to  deter- 
mine zinc  by  adding  to  an  acid  solution  an  excess  of  NaOH,  sufficient  to 
i  redissolve  the  Zn(OH)2.  The  solution  is  then  divided  exactly  in  halves;  one 
is  titrated  with  standard  acid  and  tropseolin  00  indicator,  which  gives 
Zn(OH)o-f-NaOH:  the  other  half  is  titrated  with  standard  acid  and 
phenolphthalein,  which  gives  only  the  NaOH.  The  difference  is  the  measure 
of  the  Zn  (OH)2  present.3 

Titration  with  Standard  Alkali. — P.  H.  Walker  has  described  a  method 
for  the  volumetric  determination  of  zinc  which  is  a  modification  of  that 

1  Bull.  Assoc.  Beige  des  Chim..  XI,  iv,  126-130. 

2  Journ.   Soc.   Chem.  Ind.,   May  31,  1897. 

3  Journ.  Soc.  Phys.  Chem.  Russ..  XXV,  iii,  222. 


ANAlA'fciJLJS    Ol1    ZINC    OKES   AND    PRODUCTS.  109 

devised  by  Stolba  for  the  determination  of  magnesium.  To  the  zinc  solu- 
tion, which  should  contain  ammonium  chloride,  a  large  excess  of 
ammonia  is  added,  followed  by  a  large  excess  of  sodium  phosphate 
solution.  Chlorhydric  acid  is  then  gradually  added  until,  after  stir- 
ring, the  solution  remains  milky.  It  should  then  be  heated  to  about 
75°  C.,  and  the  gradual  addition  of  acid  continued,  with  constant  stirring, 
until  nearly  complete  neutralization  is  attained.  By  this  means  the  precipi- 
tate becomes  crystalline ;  after  standing  five  minutes  it  should  be  filtered  off 
and  washed  with  cold  water  until  the  washings  show  only  a  faint  trace  of 
chlorine.  The  filter  paper  and  precipitate  are  then  returned  to  the  beaker 
in  which  the  precipitation  was  carried  out,  an  excess  of  standard  acid  is 
added,  and  the  exact  point  of  neutrality  is  determined  by  means  of  standard 
alkali,  using  methyl  orange  as 'indicator. 

The  reaction  which  takes  place  is  represented  by  the  following  equation : 

ZnNH4P04+H2S04=rZnS04+NH4H2P04. 

Calculation  from  the  above  equation  shows  that  1  c.c.  of  normal  acid 
corresponds  with  32-7  mg.  of  zinc. 

The  method  gives  good  results.  Since  the  zinc  ammonium  phosphate  is 
not  precipitated  in  presence  of  a  large  excess  of  ammonia,  any  magnesium 
present,  which  will  be  precipitated,  may  be  removed  by  filtration,  and  the 
filtrate  neutralized  to  throw  down  the  zinc.  Fairly  good  results  are  obtained 
by  this  method  also  in  the  presence  of  iron,  calcium  and  magnesium,  but 
any  manganese  must  be  previously  separated,  best  by  means  of  nitric  acid 
and  potassium  chlorate.1 

Titration  with  Sodium  Thiosulphate. — R.  K.  Meade  has  described  a 
method  for  determining  zinc  by  titration  with  a  standard  solution  of 
sodium  thiosulphate.  Manganese  is  first  thrown  down  as  dioxide  by  means 
of  potassium  chlorate  and  nitric  acid.  After  filtering,  the  iron  and  alumina 
are  separated  by  double  ammonia  precipitations.  Calcium  and  magnesium 
arc  removed  by  the  addition  of  a  large  excess  of  sodium  arsenate,  and  then 
the  zinc  is  precipitated  by  adding  nitric  and  acetic  acids.  The  iodine 
liberated  by  digesting  this  precipitate  in  an  acid  solution  of  potassium  iodide 
is  titrated  with  standard  thiosulphate  and  the  amount  of  zinc  calculated. 
The  time  required  for  four  determinations,  without  any  effort  at  speed,  was 
about  eight  hours.  The  ore  tested  contained  30-18%  Zn;  the  method  de- 
scribed gave  30-00,  29-98,  30-04  and  29-98%.2 

Pouget  has  proposed  to  pass  sulphureted  hydrogen  through  a  zinc  solu- 

1Journ.  Am.  Chem.  Soc.,  1901.  XXIII,  vii,  468-470. 
2  Ibid.,   1000,  XXII.  vl.  353. 


110  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

tion  containing  sodium  acetate,  precipitating  the  zinc  as  ZnS ;  after  boili] 
to  remove  the  excess  of  H2S  the  sulphur  of  the  ZnS,  and  consequently  tl 
zinc,  is  estimated  by  the  addition  of  iodine  solution  and  titration  wit 
standardized  sodium  thiosulphate.1 

P.  Knaps  has  also  described  a  method  for  the  determination  of  zinc  b] 
means  of  iodine  solution.  Zinc  sulphide,  in  the  acetic  solution  in  which 
-it  is  ordinarily  precipitated,  is  converted  by  iodine  into  zinc  iodide  and 
sulphur.  If,  however,  more  than  0-05  g.  of  zinc  sulphide  to  200  c.c.  of 
water  be  present,  the  separated  sulphur  protects  particles  of  it  from  the 
action  of  the  iodine.  This  can  be  prevented  by  forming  a  precipitate,  such 
as  barium  sulphate,  in  the  liquid  prior  to  the  introduction  of  the  hydrogen 
sulphide.  Thus,  from  10  to  20  c.c.  of  a  solution  of  150  g.  of  barium 
chloride  in  a  liter,  and  the  same  quantity  of  sodium  sulphate  solution 
(200  g.  per  liter),  are  introduced,  the  zinc  precipitated,  and  the  excess  of 
hydrogen  sulphide  removed  by  boiling.  An  excess  of  standard  iodine  solu- 
tion is  then  added,  the  liquid  is  shaken  for  one  or  two  minutes,  and  the 
excess  of  iodine  is  titrated  with  standard  sodium  thiosulphate  solution. 
Ammonium  salts  do  not  interfere,  and  the  results  are  accurate  even  in  the 
presence  of  considerable  quantities  of  manganese  salts.2 

Electrolytic  Assay. — H.  Paweck  described  a  method  for  the  estimation  of 
zinc  electrolytically,  employing  a  platinum  anode  and  a  cathode  consisting 
of  an  amalgamated  brass  wire  gauze  disk,  6  cm.  in  diameter,  suspended  from 
the  center  by  a  1  mm.  wire.  The  electrolyte,  about  200  c.c.  in  volume,  may 
be  either  acid  or  alkaline;  a  current  of  3-6  volts  is  used.  Results  are  said 
to  be  fairly  satisfactory  as  to  accuracy.3 

Gravimetric  Method  by  Precipitation  as  Sulphide. — J.  Meunier  states  that 
the  difficulty  experienced  in  collecting  zinc  sulphide  for  gravimetric  deter- 
mination is  overcome  in  the  following  simple  manner:  The  zinc  solution, 
preferably  slightly  warmed,  is  precipitated  with  ammonia,  just  sufficient  of 
the  precipitant  being  cautiously  added  to  redissolve  the  hydrate  at  first 
formed.  A  slow  current  of  sulphureted  hydrogen  is  then  passed  through  the 
solution  until  a  drop  of  it,  on  a  white  tile,  gives  a  blackish  coloration  with 
another  drop  of  a  solution  of  ferrous  sulphate.  When  this  occurs  the  whole 
of  the  zinc  will  have  been  precipitated,  and  is  in  a  suitable  condition  for 
collection.  The  passage  of  the  gas  is  immediately  stopped  and  the  zinc 
sulphide  collected,  washed,  and  dried  in  the  usual  way.  It  will  be  found 
that  the  filtrate  will  at  once  run  perfectly  clear,  and  that  the  precipitate 
may  be  rapidly  washed,  especially  if  warm  solutions  be  employed.  The 

1  Comptes  Rendus,  CXXIX,  45.  *  Chem.  Ztg.,  XXV,  539-540. 

"Zeits.  f.  Elektrochem.,  1898,    XVIII,  221. 


ANALYSIS    OF    ZINC    ORES    AND    PRODUCTS.  HI 

presence  of  large  quantities  of  other  salts  does  not  affect  the  ease  and 
rapidity  with  which  the  process  may  be  conducted.1 

DETERMINATION  OF  CADMIUM. 

There  are  numerous  good  methods  for  the  determination  of  cadmium, 
but  as  in  the  case  of  zinc  there  is  none  better  for  ordinary  technical  pur- 
poses than  the  ferrocyanide  method,  which  is  applicable  to  cadmium  in 
the  same  way  as  to  zinc.  Inasmuch  as  cadmium  occurs  generally  with 
zinc  and  it  is  desirable  to  estimate  both  elements,  a  convenient  combination 
of  methods  can  be  made  whereby  both  can  be  determined  from  the  same 
sample.  To  do  that  the  sample  should  be  treated  as  described  under  the 
caption  of  the  von  Schulz  and  Low  process  of  1900.  The  cadmium  and 
copper  sulphides  precipitated  by  means  of  hydrogen  sulphide  are  filtered  off. 
The  filtrate  is  used  for  the  determination  of  zinc  in  the  regular  manner. 
The  precipitate  is  washed  with  a  solution  of  hydrogen  sulphide  and  then 
dissolved  in  a  little  hot,  dilute  chlorhydric  acid.  The  solution  should  then  be 
further  diluted  and  the  copper  precipitated  by  means  of  test  lead  or 
aluminum  foil  in  the  conventional  manner.  If  no  copper  be  present 
that  step  will  of  course  be  omitted. 

Inasmuch  as  zinc  may  be  to  some  extent  dragged  down  with  the  sulphides 
precipitated  with  sulphureted  hydrogen,  it  is  advisable  to  redissolve  them 
in  chlorhydric  acid  and  precipitate  them  a  second  time.  Or  the  chlorhydric 
acid  solution  may  be  heated  to  boiling  and  then  be  poured  into  an  excess  of 
cold  sodium  hydrate  solution,  whereby  insoluble  cadmium  hydroxide  is 
thrown  down,  while  the  zinc  hydroxide  is  kept  in  solution  by  the  excess  of 
caustic  soda.  The  cadmium  precipitate  is  then  filtered  off,  redissolved  in 
chlorhydric  acid  and  proceeded  with  in  the  usual  manner. 

The  solution  freed  from  copper  is  then  ready  for  titration  with  the 
standard  solution  of  potassium  ferrocyanide,  using  uranium  nitrate  as  in- 
dicator. The  same  solution  may  be  used  for  cadmium  as  for  zinc ;  the  zinc 
equivalent  in  milligrams  per  1  c.c.  is  to  the  cadmium  equivalent  as 
654:112-3,  those  figures  being  respectively  the  atomic  weights  of  zinc 
and  cadmium.  If  many  determinations  of  cadmium  have  to  be  made,  how- 
ever, it  is  preferable  to  prepare  a  special  solution  of  potassium  ferro- 
cyanide, about  58%  as  strong  as  that  used  for  zinc,  and  standardize  it 
against  a  known  weight  of  chemically  pure,  metallic  cadmium. 

Numerous  methods  for  the  determination  of  cadmium  which  are  em- 
ployed in  European  laboratories  are  described  in  Das  Cadmium,  a  pamphlet 

1  Comptes  Rendus,  OXXIV,  xxi,  1151. 


112  PRODUCTION  AND  PROPERTIES  OE  ZINC. 

by  E.  Jensch,  reprinted  from  Sammlung  Chemischer  und  Chemischtet 
nischer  Vortr'dge,  III,  vi,  (1898).  In  general,,  these  are  gravimetric  metl 
ods  in  which  the  cadmium  is  weighed  as  sulphide  on  a  tared  filter,  or 
oxide  obtained  by  calcination  of  a  final  precipitate  of  hydroxide  or  carbonate. 
E.  H.  Miller  and  R.  W.  Page  have  recently  investigated  several  methods 
for  the  quantitative  determination  of  cadmium.1  They  found  the  elec- 
trolytic method  to  be  very  accurate  if  a  large  excess  of  potassium  cyanide 
and  the  presence  of  other  salts  be  avoided.  The  carbonate  method  is  the 
most  troublesome  and  the  least  accurate.  A  very  accurate  method  is  the 
precipitation  of  cadmium  from  a  neutral  solution  (cold)  by  a  large  excess 
of  di-ammonium  hydrogen  phosphate  and  either  weighing  the  precipitate 
as  CdNH4P04,H20  on  a  tared  filter  (after  drying  at  100°  to  103°  C.),  or 
dissolving  it  in  dilute  nitric  acid  and  igniting  to  pyrophosphate. 


DETERMINATION  OF  LEAD. 

of 


The  zinc  smelter  is  frequently  required  to  determine  the  percentage  o 
lead  in  ore  and  spelter.  The  latter  is  commonly  done  gravimetrically, 
weighing  the  lead  as  sulphate  as  described  in  a  subsequent  section.  The 
percentage  of  lead  in  ore  is  determined  most  conveniently  by  volumetric 
analysis,  the  permanganate,  the  molybclate  and  the  ferrocyanide  methods 
all  being  satisfactory  with  respect  to  speed,  simplicity  and  the  degree  of 
accuracy  required  for  technical  purposes. 

Ammonium  Molybdate  Method. — This  method,  which  is  due  to  H. 
Alexander,  is  based  upon  the  fact  that  ammonium  molybdate  added  to 
hot  solution  of  lead  acetate  will  precipitate  lead  molybdate,  PbMo04,  whi 
is  insoluble  in  acetic  acid,  while  an  excess  of  the  ammonium  molybdate 
will  give  a  yellow  color  with  a  freshly  prepared  solution  of  tannin.  The 
standard  solution  of  ammonium  molybdate  is  prepared  by  dissolving  9  g. 
of  the  salt  in  1,000  c.c.  of  water,  affording  a  solution  of  which  1  c.c.  is 
equal  to  about  0-01  g.  of  lead.  If  the  solution  be  turbid,  it  can  be  clarified 
by  adding  a  few  drops  of  ammonia  water.  The  tannin  solution  is  prepared 
by  dissolving  1  g.  of  tannin  in  300  c.c.  of  water;  it  is  used  on  a  po 
test  plate.  To  standardize  the  molybdate  solution,  weigh  out  0-3  g.  of  p 
lead  sulphate  and  dissolve  it  in  hot  ammonium  acetate,  acidify  the  solution 
with  acetic  acid  and  dilute  with  hot  water  to  250  c.c.  Heat  to  boiling 
then  titrate  with  the  molybdate  solution  until  all  the  lead  is  thrown  do 
as  a  white  precipitate,  which  is  ascertained  by  testing  the  solution  from  time 
to  time  with  a  drop  of  the  tannin  solution  on  a  porcelain  plate.  So  long  as 

School  of  Mines  Quarterly.   1901,  XXII,  iv.  391-398. 


ANALYSIS    OF    ZINC    ORES    AND    PRODUCTS.  113 

the  lead  is  in  excess  no  color  is  produced,  but  as  soon  as  the  lead  is  pre- 
cipitated the  excess  of  the  molybdate  shows  a  yellow  color  with  the  tannin 
solution. 

In  determining  the  lead  in  an  ore  or  furnace  product  by  this  method 
1  g.  of  the  sample  is  decomposed  by  heating  in  a  casserole  with  15  c.c.  of 
strong  nitric  acid  and  10  c.c.  of  strong  sulphuric  acid.  When  the  nitric 
acid  is  completely  expelled,  which  is  indicated  by  the  appearance  of  fumes 
of  sulphuric  anhydride,  the  casserole  is  removed  from  the  heat  and  cooled. 
Its  contents  are  then  diluted  with  hot  water,  stirred  thoroughly  and  boiled 
until  all  soluble  sulphates  are  dissolved.  Then  filter,  leaving  as  much  of 
the  precipitate  in  the  casserole  as  possible  and  wash  twice  with  hot,  dilute 
sulphuric  acid  and  once  with  cold  water.  Then  add  to  the  lead  sulphate 
remaining  in  the  casserole  hot  ammonium  acetate,  pour  the  hot  solution  on 
the  filter,  and  allow  it  to  run  through  into  a  clean  beaker.  This  operation 
is  repeated  until  the  lead  sulphate  is  completely  dissolved.  Then  wash 
out  the  casserole  thoroughly  with  hot  water  into  the  filter.  Dilute  the 
solution  to  250  c.c.  with  hot  water  and  heat  to  boiling.  Then  titrate  with 
the  ammonium  molybdate.1 

A  determination  can  be  made  readily  by  means  of  the  molybdate  method 
in  30  minutes.  It  gives  excellent  results  in  the  presence  of  the  most  com- 
mon impurities,  but  fails  when  lime  is  present,  owing  to  the  precipitation 
of  calcium  molybdate.  In  the  case  of  calcareous  ores  a  combination  of  the 
permanganate  method  and  the  molybdate  method  may  be  made,  the  former 
being  followed  up  to  the  point  of  precipitation  of  the  lead  by  zinc.  The 
precipitated  lead  should  then  be  dissolved  in  dilute  nitric  acid,  using  as 
small  quantity  as  possible,  after  which  the  solution  should  be  made  alkaline 
with  ammonia,  and  then  neutralized  with  acetic  acid.  The  titration  with 
ammonium  molybdate  may  then  be  proceeded  with.2 

Potassium  Permanganate  Method. — In  the  employment  of  this  method, 
which  was  devised  by  Mr.  F.  C.  Knight,  1  g.  of  ore  is  treated  with  15  c.c. 
of  strong  nitric  acid  and  15  c.c.  of  strong  sulphuric  acid  in  a  4  in.  casserole, 
covered  with  a  watch  glass.  Heat  until  decomposition  is  complete  and 
fumes  of  sulphuric  anhydride  appear.  Then  remove  the  casserole  and  when 
it  is  cool  add  gradually  about  50  c.c.  of  cold  water,  heat  to  boiling  and 
filter  immediately.  Wp.sh  well  with  boiling  water,  slightly  acidified  with 
sulphuric  acid,  and  finally  with  pure  hot  water.  Einse  the  insoluble  residue 
into  a  beaker  of  about  200  c.c.  capacity,  using  not  to  exceed  50  c.c.  of  water; 
add  5  c.c.  of  concentrated  chlorhydric  acid,  cover  with  a  watch  glass  and 

iH.    H.    Alexander,    Eng.    &   Min.    Journ.,Apr.  1,  1893.  p.  298. 
2  H.  van  F.  Furman.  Manual  of  Assaying,  third  edition,  p.  142. 


114  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

boil  for  five  minutes.  The  sulphates  of  lead  and  lime  pass  into  solution.  If 
much  silica  and  barium  sulphate  be  present  it  is  best  to  filter  and  wash 
well  with  boiling  water.  The  filtration  must  be  done  rapidly.  Small 
quantities  of  silica  do  not  interfere,  but  large  quantities  prevent  a  subse- 
quent precipitation  of  the  lead  in  one  spongy  mass. 

Dilute  the  solution  with  water  to  about  100  e.c.,  keeping  it  hot  but  n 
boiling.     Add  2  g.  of  granulated  zinc   (free  from  lead),  which  will  p 
cipitate  the  lead  in  the  solution  as  a  metallic  sponge.    When  the  action 
the  acid  on  the  zinc  has   apparently  ceased  add   0-5   g.   more   of   zinc 
and  allow  to  stand  for  five  minutes.     Then  boil  the  solution  and  ad 
10  c.c.  of  concentrated  chlorhydric  acid,  which  dissolves  the  remainder 
the  zinc  and  leaves  the  lead  sponge  floating  on  the  surface  of  the  solutio: 
Decant  off  the  solution,  wash  the  lead  sponge  with  cold  water  and  press 
out  flat  with  the  finger.     Then  dissolve  it  in  1  c.c.  of  concentrated  nit 
acid  and  20  c.c.  of  hot  water,  add  a  slight  excess  of  sodium  carbonate1  an 
rcdissolve  the  precipitated  lead  carbonate  by  the  addition  of  5  c.c.  of  strong 
acetic  acid.    Add  20  c.c.  of  95%  alcohol,  heat  the  solution  to  65°  C.  and 
precipitate  the  lead  with  a  saturated  solution  of  pure  crystallized  oxali 
acid.    The  lead  comes  down  immediately  as  a  dense,  white,  crystalline  pre 
cipitate.     Stir  briskly  until  the  precipitate  settles,  leaving  a  perfectly  clea 
supernatant  liquid.    Filter  and  wash  the  precipitate  three  times  with  a  ho 
mixture  of  alcohol  and  water  (1:1)  and  then  four  times  with  hot  wate 
alone.    In  washing  the  precipitate  it  is  advisable  to  use    a  fine  jet,  keepin 
the  stream  on  the  filter  and  not  allowing  it  to  flow  on  the  glass,  since  other 
wise  the  precipitate  is  likely  to  creep  up  and  thereby  occasion  loss.    Whei 
thoroughly  washed  the  precipitate  is  rinsed  into  a  flask  or  beaker  with 
about  50  c.c.  of  hot  water  and  5  c.c.  of  concentrated  sulphuric  acid, 
oxalic  acid  combined  with  the  lead  and  set  free  by  the  sulphuric  acid 
then  determined  by  titration  with  a  standard  solution  of  potassium  p 
manganate,  in  the  same  way  as   for  the  determination   of  lime, 
potassium  permanganate  solution  should  be  prepared  by  dissolving  1-58 
of  KMn04  in  1,000  c.c.  of  water.     One  cubic  centimeter  of  a  solution 
that  strength  is   equivalent  to  about   0-05   g.    of  lead.     The  solution 
standardized  against  oxalic  acid,  the  equivalent  in  terms  of  lead  bei 
calculated  by  multiplying  the  oxalic  equivalent  by  1-6428.2 

There  are  no  metallic  impurities  likely  to  be  encountered  in  zinc  ores 
furnace  products  which  interfere  with  the  accuracy  of  this  method, 
determination  can  be  made  in  35  to  40  minutes.    The  disadvantage  of  the 

1  The  solid  salt  is  preferable  to  the  solution. 

2  Proc.  Colo.  Scientific  Society,  IV,  215  to  223. 


ANALYSIS    OF   ZIXC    ORES    AND    PRODUCTS.  H5 

method  is  that  the  result  is  liable  to  be  a  little  low  on  account  of  the  incom- 
plete precipitation  of  the  lead  as  oxalate.  According  to  Mr.  Knight  about 
99-75%  of  the  lead  present  is  obtained.  This  inaccuracy  is  of  jminor 
importance  in  connection  with  the  low  percentages  of  lead  that  the  zinc 
smelter  finds  in  his  products  and  otherwise  the  permanganate  method  is  a 
very  good  one. 

Potassium  Ferrocyanide  Method. — The  estimation  of  lead  by  titration 
with  a  standard  solution  of  potassium  ferrocyanide  is  highly  recommended 
by  Furman,  in  his  Manual  of  Practical  Assaying,  who  states  that  1  g.  of 
the  sample  should  be  treated  in  the  same  manner  as  with  Alexander's 
method  up  to  the  point  where  the  lead  is  precipitated  as  sulphate.  The 
precipitate  of  lead  sulphate  should  be  washed  and  then  transferred  into 
the  flask  or  beaker  with  the  use  of  the  minimum  quantity  of  water.  Add 
30  c.c.  of  a  saturated  solution  of  .ammonium  carbonate,  heat  quickly  to 
boiling  and  boil  at  least  one  minute  in  order  to  decompose  any  calcium 
sulphate  which  may  have  formed.  It  is  essential  that  calcium  sulphate  be 
converted  into  carbonate,  since  otherwise  it  would  react  upon  the  dissolved 
lead  and  cause  low  results.  Filter  and  wash  thoroughly  with  hot  water 
containing  a  little  ammonium  carbonate.  Dissolve  the  washed  carbonate 
of  lead  in  strong  acetic  acid,  dilute  to  about  180  c.c.  and  titrate  with  the 
standard  solution  of  potassium  ferrocyanide  in  the  same  manner  as  for 
zinc.  The  ferrocyanide  solution  should  contain  14  g.  of  the  salt  per  liter, 
and  when  of  that  strength  one  cubic  centimeter  will  be  equivalent  to  about 
0-01  g.  of  lead. 

DETERMINATION  OF  IRON. 

The  methods  of  determining  the  percentage  of  iron  in  ores  are  so  nu- 
merous that  they  cannot  be  described  properly  except  in  a  special  treatise  on 
analytical  chemistry.  It  will  be  sufficient  here  to  refer  only  to  the  method 
of  titration  with  potassium  permanganate,  which  is  the  quickest  and  most 
easily  performed  of  all  the  methods  of  determining  iron  and  if  properly 
carried  out  gives  results  which  answer  all  the  purposes  of  technical  analysis. 
The  potassium  permanganate  method  is  based  on  the  measurement  of  the 
volume  of  the  reagent  required  to  oxidize  the  iron  from  the  ferrous  to  the 
ferric  state,  a  pink  color  being  imparted  to  the  solution  the  moment  the 
conversion  is  complete.  It  is  essential  therefore  after  effecting  a  solution 
of  the  iron  of  a  sample  to  reduce  it  completely  to  the  ferrous  condition 
before  subjecting  it  to  titration. 

The  standard  solution  of  potassium  permanganate  is  prepared  by  dis- 
solving 5-9  g.  of  the  pure  crystallized  salt  in  1,000  c.c.  of  water.  This 


116  PRODUCTION  AND  PHOPEKT1KS  OF  ZINC. 

solution  should  be  made  up  at  least  48  hours  before  standardizing,  should 
be  kept  in  a  well-stoppered  bottle  and  should  be  well  shaken  before  use.  The 
solution,  if  carefully  kept  (action  of  direct  sunlight  should  be  avoided),  does 
not  alter,  but  it  is  well  to  titrate  it  afresh  occasionally.  It  is  standardized 
against  metallic  iron,  the  latter  being  used  generally  in  the  form  of  fine 
soft  iron  wire  which  contains  99-6  to  99-7%  Fe.  About  200  mg.  of  the 
latter  are  weighed  out  and  dissolved  in  10  c.c.  of  dilute  sulphuric  acid 
by  gently  warming  in  a  250  c.c.  flask.  To  the  solution,  diluted  with  about 
100  c.c.  of  water,  a  small  quantity  of  pure  granulated  zinc  is  added,  which 
has  the  effect  of  reducing  ferric  sulphate  to  ferrous  sulphate,  the  solution 
becoming  colorless  when  the  reduction  is  complete.  The  loss  of  color  is  not, 
however,  a  sufficiently  accurate  guide,  since  some  of  the  ferric  iron  may 
remain  when  the  solution  is  apparently  devoid  of  color.  The  completeness 
of  the  reduction  should  be  tested  therefore  by  removing  a  drop  of  the 
solution  on  a  glass  rod  to  a  porcelain  plate  and  adding  a  drop  of  ammonium 
sulphocyanate  solution;  if  the  iron  be  completely  reduced  to  the  ferrous 
condition  the  drop  will  remain  colorless,  while  jf  any  ferric  salt  be  present 
it  will  turn  red,  the  depth  of  the  color  depending  on  the  quantity  of  ferric 
iron  present.  The  reduction  being  complete,  the  contents  of  the  flask  are 
further  diluted  by  the  addition  of  cold  water  and  then  decanted  from  the 
undissolved  zinc  into  a  large  beaker,  the  flask  and  the  zinc  being  well 
washed  and  the  washings  added  to  the  original  solution.  The  solution  is 
then  made  up  to  about  700  c.c.  and  about  20  c.c.  of  dilute  sulphuric  acid 
are  added.  The  titration  with  potassium  permanganate  is  then  proceeded 
with,  and  the  iron  equivalent  of  the  standard  solution  is  calculated  from 
the  number  of  cubic  centimeters  used.  The  solution  containing  the  iron 
should  not  be  permitted  to  stand  too  long  before  beginning  the  titration, 
since  some  of  the  iron  is  likely  to  be  reoxidized  by  exposure  to  the  air ;  all 
evolution  of  gas  from  the  action  of  sulphuric  acid  on  minute  particles  of 
zinc  decanted  over  with  the  washings  should  have  ceased,  however,  before 
beginning  the  titration.  The  end-point  of  the  reaction  is  manifested  when 
one  drop  of  the  permanganate  produces  a  pink  coloration  in  the  solution 
under  analysis  which  cannot  be  stirred  out.  The  fact  that  the  color  may 
disappear  after  a  time  need  cause  no  uneasiness,  however,  since  that  is 
one  of  the  results  of  the  natural  conditions  involved  in  the  reactions. 

The  potassium  permanganate  solution  may  also  be  standardized  against 
oxalic  acid,  250  mg.  of  the  latter  being  weighed  out  and  dissolved  in  100  c.c. 
of  water.  Then  add  6  to  8  c.c.  of  pure  concentrated  sulphuric  acid,  heat 
to  about  70°  C.  and  run  in  the  permanganate  solution  until  a  permanent 
color  is  obtained.  The  color  will  disappear  very  slowly  at  first,  but  after 


ANALYSIS    OF    ZINC    OKES    AND    PRODUCTS.  11T 

a  small  quantity  of  the  permanganate  solution  has  been  added  it  will  dis- 
appear rapidly.  Owing  to  the  smaller  bulk  of  the  oxalic  acid  solution  as 
compared  with  the  iron  solution,  when  the  standardization  is  performed  by 
the  former  method,  one  or  two  drops  less  of  the  permanganate  solution  are- 
required  and  allowance  should  be  made  for  them.  In  standardizing  against 
oxalic  acid  the  equivalent  of  iron  is  calculated  on  the  assumption  that 
250  mg.  of  oxalic  aeid=222  nig.  of  iron.  Care  must  be  taken  that  the 
oxalic  acid  employed  be  pure  and  perfectly  dry.  Instead  of  oxalic  acid,  the 
permanganate  may  be  standardized  against  crystallized  ammonium  oxalate 
r(NH4)C204+H20],  which  can  be  easily  prepared  in  the  pure  state  and 
keeps  well;  142-08  parts  of  that  salt  correspond  to  112  parts  of  iron. 

To  determine  the  percentage  of  iron  in  blende,  dissolve  1  g.  of  ore  in  a 
small  casserole  with  4  c.c.  of  strong  chlorhydric  acid,  10  c.c.-  of  strong  nitric 
acid  and  15  c.c.  of  dilute  (1:1)  sulphuric  acid  added  in  the  order  men- 
tioned. Heat  on  a  sand  bath  or  iron  plate  until  dense  white  fumes  of 
sulphuric  anhydride  are  evolved,  and  then  for  about  three  minutes  longer 
in  order  to  be  sure  of  removing  the  last  traces  of  nitric  acid,  which  is 
essential.  Then  cool  and  add  about  50  c.c.  of  water.  Pour  the  solution 
into  a  flask,  washing  out  the  casserole  and  adding  the  washings  to  the 
solution  in  the  flask.  Add  metallic  zinc  to  reduce  the  ferric  sulphate  and 
then  proceed  in  the  same  manner  as  in  the  standardization  against  metallic 
iron. 

If  the  proper  precautions  are  observed,  iron  in  a  chlorhydric  acid  solution, 
may  be  determined  by  titration  with  potassium  permanganate,  although  it 
is  frequently  asserted  that  this  method  is  not  accurate.  Furman  states,  how- 
ever, that  if  only  a  small  quantity  of  chlorhydric  acid  be  present  and  the 
solution  is  extremely  dilute  (700  c.c.)  and  cold  and  moreover  contains  a  large 
excess  of  sulphuric  acid  (usually  20  c.c.  of  concentrated  acid),  the  results 
obtained  are  as  reliable  as  when  sulphuric  acid  is  used  as  the  solvent.  A* 
a  further  precaution  some  chemists  add  a  few  cubic  centimeters  of  a 
saturated  solution  of  manganous  sulphate  before  titration,  but  that  is  un- 
necessary if  the  above  conditions  are  carried  out;  however,  inasmuch  as 
the  addition  of  manganous  sulphate  can  do  no  harm  it  is  well  to  use  it 
when  in  doubt  or  when  'a  considerable  quantity  of  chlorhydric  acid  ha* 
been  employed.1  Beringer  has  also  shown  that  good  results  may  be  obtained 
with  the  use  of  a  chlorhydric  acid  solution,  if  the  acid  be  not  greatly  in- 
excess.2 

To  determine  the  percentage  of  iron  in  oxidized  ores  dissolve  1  g.  in  a 
small  casserole  with  5  c.c.  of  chlorhydric  acid.  Dilute  with  water,  filter  and 

2Op.  cit,  p.  173.  2  Textbook  of  Assaying,  p.  200. 


118  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

reduce  the  iron  in  the  solution  by  means  of  metallic  zinc.  Then  titrate  as 
in  standardizing  against  iron.  Most  ores  will  yield  their  iron  by  a  simple 
boiling  with  chlorhydric  acid.  If  the  sample  be  a  furnace  product  which 
perhaps  cannot  be  decomposed  in  that  manner,  use  the  three  acids  as  in 
dealing  with  a  sulphide  ore. 

In  case  the  ore  is  to  be  digested  with  chlorhydric  acid  and  that  solution  is 
to  be  titrated,  it  is  advisable  to  dissolve  the  iron  for  standardization  in 
chlorhydric  acid  also  in  order  that  the  conditions  may  be  precisely  the 
same.  However,  if  the  solutions  contain  only  from  5  to  10%  of  free 
chlorhydric  acid  the  results  will  be  the  same  as  those  obtained  from  a 
sulphuric  acid  solution. 

DETERMINATION  OF  LIME  AND  MAGNESIA. 

Lime  is  most  easily  determined  by  precipitating  it  as  oxalate  from 
solutions,  decomposing  the  calcium  oxalate  by  dilute  sulphuric  acid  and 
titrating  the  oxalic  acid  thus  liberated  with  potassium  permanganate.  The 
permanganate  solution  may  be  the  same  as  is  used  for  the  determination 
of  iron  and  may  be  standardized  in  the  same  manner.  If  it  be  made  up  of 
such  strength  that  1  c.c.=O01  g.  of  iron,  1  c.c.  will  be  equal  to  0-005  g.  of 
lime.  There  is  no  convenient  method  for  the  volumetric  determination  of 
magnesia,  and  that  is  commonly  estimated  gravimetrically  as  described  by 
Fresenius. 

Lime. — In  determining  lime  weigh  up  1  g.  of  ore  and  digest  with  6 
or  7  c.c.  of  chlorhydric  acid,  adding  a  few  drops  of  nitric  acid  to  aid  in 
the  decomposition  of  any.  sulphides  that  may  be  present.  If  there  be  no 
sulphides  the  nitric  acid  may  be  omitted.  In  the  case  of  sulphide  ores 
it  is  best  to  decompose  with  a  mixture  of  4  c.c.  of  strong  chlorhydric  acid 
and  3  c.c.  of  strong  nitric.  The  solution  is  then  evaporated  to  dryness  and 
heated  to  about  120°  C.  to  drive  off  the  free  chlorhydric  acid  and  render  the 
silica  insoluble,  after  which  the  soluble  matter  is  taken  up  again  by  boiling 
with  a  few  cubic  centimeters  of  chlorhydric  acid,  diluted  with  water  and 
filtered.  If  the  ore  be  argillaceous  and  likely  to  contain  lime  as  silicate  the 
sample  must  first  be  fused  with  5  or  6  g.  of  sodium  carbonate,  because  cal- 
cium silicate  is  not  completely  decomposed  by  chlorhydric  acid.  The  fused 
mass  is  then  digested  with  water  and  chlorhydric  acid  in  slight  excess  and 
the  solution  evaporated  and  taken  up  again  as  before  described.  In  case 
barium  sulphate  and  lead  sulphate  be  absent,  the  insoluble  residue  may  be 
washed,  ignited  and  weighed  as  silica.  Lead  sulphate,  which  will  be  formed 
by  the  oxidation  of  the  sulphide  by  nitric  acid,  may  be  dissolved  by  treat- 
ment with  a  warm  solution  of  ammonium  acetate. 


ANALYSIS    OF    ZINC    ORES    AND   PRODUCTS.  119 

The  solution  in  which  lime  is  to  be  determined  must  be  free  from  lead, 
iiich  if  present  must  be  precipitated  by  sulphureted  hydrogen  or  otherwise. 
•on  and  aluminum  are  then  removed  by  precipitation  with  ammonia,  and 
nally  calcium  is  precipitated  as  oxalate  by  the  addition  of  ammonium 
valate  or  oxalic  acid.  The  solution  in  which  the  precipitation  is  made 
iould  not  be  much  over  100  c.c.  in  bulk.  If  oxalic  acid  be  used  as  the 
recipitant  there  should  be  a  sufficient  excess  of  ammonia  present  to  insure 
lat  the  solution  will  be  alkaline  after  the  addition  of  the  acid.  If  mag- 
.-sia  be  present  the  ammonium  oxalate  should  be  in  considerable  excess 
i  order  to  insure  that  all  the  magnesia  will  be  converted  into  oxalate, 
Inch  is  soluble.  The  contents  of  the  beaker  must  then  be  heated  to  boiling 
>r  a  few  minutes  and  filtered  immediately,  whereby  there  will  be  no  danger 

the  calcium  oxalate  running  through  the  filter  paper.  If  there  be  no 
:agnesia  present  the  precipitate  is  washed  with  boiling  water  until  the 
ashings  cease  to  give  a  reaction  for  oxalic  acid.  The  filter  paper  with  its 
mtents  is  then  spread  out  on  a  watch  glass  somewhat  larger  than  the  paper, 
nd  the  precipitate  is  washed  off  with  hot  water  from  a  wash-bottle  with  a 
ne  jet  into  a  beaker,  the  washing  being  finished  with  some  dilute  sulphuric 
:-id  used  in  the  same  manner. 

If  magnesia  be  present  it  is  safest  to  redissolve  the  precipitate  in  chlor- 
ydric  acid,  which  is  done  conveniently  by  spreading  the  filter  paper  on  a 
atch  glass  and  washing  the  precipitate  into  a  beaker  as  described  above, 
nishing  with  chlorhydric  acid  instead  of  sulphuric.  The  chlorhydric  acid 
lould  be  hot  and  dilute  and  as  little  of  it  should  be  used  as  possible.  The 
iilorhydric  acid  solution  should  then  be  diluted  with  boiling  water  to  about 
"  c.c.,  and  after  being  made  alkaline  with  ammonia  about  20  c.c.  of  am- 
loniuni  oxalate  solution  should  be  added  and  the  contents  of  the  beaker 
eated  nearly  to  boiling.  The  precipitate  is  then  to  be  filtered  off  and 
•ashed  into  a  beaker  as  described  above. 

To  the  precipitate  washed  into  the  beaker  with  the  aid  of  hot  water  and 
ilute  sulphuric  acid  about  10  to  15  c.c.  of  sulphuric  acid  should  be  carefully 
dded  and  the  solution  heated  to  about  70°  or  80°  C.,  when  it  is  ready  for 
itration  with  the  standard  solution  of  potassium  permanganate.  The  latter 
hould  be  run  in  with  moderate  rapidity  and  with  constant  stirring  of  the 
olution  until  a  permanent  pink  tinge  is  produced,  indicating  the  end-point 
f  the  reaction.  The  percentage  of  lime  is  then  calculated  from  the  number 
•f  cubic  centimeters  of  the  permanganate  solution  used.  The  results  are 
ery  accurate.  The  titration  is  very  conveniently  performed  in  an  evaporat- 
ng-dish,  the  opaque  white  of  which  constitutes  a  good  background  in  deter- 
nining  the  end-point  of  the  reaction. 


120  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

Magnesia. — The  filtrates  from  the  precipitation  of  the  lime  as  oxalate  may 
be  employed  for  the  determination  of  magnesium,  which  is  commonly  done 
by  precipitating  that  metal  as  ammonium-magnesium  phosphate,  which 
is  converted  into  magnesium  pyrophosphate  (Mg2P207)  by  ignition  and 
weighed  as  such.  The  precipitation  is  effected  by  the  addition  of  an 
excess  of  a  W%  solution  of  hydrodisodium  phosphate  (Na2HP04).1  Both 
the  solutions  should  be  cold.  After  adding  the  phosphate  solution  the  con- 
tents of  the  beaker  should  be  stirred  with  a  glass  rod,  care  being  taken  not 
to  touch  the  sides  of  the  beaker,  which  would  cause  crystals  of  ammonium- 
magnesium  phosphate  to  adhere  thereto  so  firmly  that  it  is  difficult  to 
remove  them.  It  is  advisable  to  set  the  beaker  in  a  dish  containing  cold 
water  and  stir  frequently,  since  a  low  temperature  and  agitation  of  the  solu- 
tion facilitate  the  precipitation.  The  solution  must  then  be  allowed  to 
stand,  without  warming,  for  some  time  (up  to  12  hours)  to  insure  complete 
precipitation.  When  1  g.  of  sample  has  been  used  for  the  analysis  it  can  be 
assumed  that  10  c.c.  of  the  hydrodisodium  phosphate  solution  of  the 
strength  specified  above  will  be  sufficient  to  precipitate  all  the  magnesium  if 
the  latter  be  not  in  excess  of  10%. 

The  solution  from  which  magnesia  is  to  be  precipitated  must  be  free  from 
iron  and  alumina  and  the  metals  which  are  thrown  down  by  sulphureted 
hydrogen,  including  zinc  and  manganese.  The  analytical  scheme  for  sub- 
stances containing  those  metals  will,  therefore,  necessarily  provide  for  their 
removal,  which  is  of  course  best  done  before  the  precipitation  of  the  lime. 
After  the  metals  of  the  second  group  have  been  thrown  down  by  means  of 
sulphureted  hydrogen,  iron  and  aluminum  are  best  precipitated  as  basic 
acetates.  Manganese  is  then  removed  from  the  filtrate  by  oxidation  with 
bromine  water,  after  which  the  solution  is  acidified  with  acetic  acid  and  the 
zinc  precipitated  with  sulphureted  hydrogen.2 

The  precipitate  of  ammonium-magnesium  phosphate  is  collected  on  a 
small  filter  and  washed  with  dilute  ammonia  (two  or  three  parts  of  water  to 
one  part  of  ammonia  of  0-96  sp.  gr.)  until  the  washings  no  longer  show  a 
precipitate  by  the  addition  of  a  few  drops  of  silver  nitrate  solution  (acidified 
with  nitric  acid)  or  only  a  very  slight  opalescence  is  manifested.  The  pre- 
cipitate is  then  dried  and  transferred  to  a  tared  platinum  crucible ;  the  filter 
paper  is  burned  on  the  lid  of  the  crucible  until  white  and  its  ash  added  to 
the  contents  of  the  crucible.  The  crucible  must  then  be  ignited  strongly 
until  its  contents  are  white  or  nearly  so.  If  the  magnesium  pyrophosphate 
is  dark  colored,  moisten  with  a  few  drops  of  nitric  acid,  dry  carefully  and 

1  One  cubic  centimeter  of  such  a  solution  2  Vide    Fresenius,    Quantitative    Chemical 

will   precipitate  0-0112  g.   of  MgO.   Magne-       Analysis,    John    Wiley    &    Son's    edition    of 
Blum  pyrophosphate  contains  36-036%  MgO.        1883,  pp.  517,  519  and  755. 


ANALYSIS    OF    ZINC    ORES    AND    PRODUCTS.  121 

ignite  again.  The  weight  of  the  ignited  precipitate  multiplied  by  0-36036 
Avill  give  the  weight  of  the  equivalent  in  magnesia,  from  which  the  per- 
centage in  the  ore  can  be  calculated. 

This  method,  if  properly  executed,  gives  very  accurate  results.  The  pre- 
cipitate must  be  washed  completely,  but  not  overwashed,  and  the  washing- 
water  must  always  contain  the  prescribed  quantity  of  ammonia.  Instead 
of  igniting  and  weighing  the  precipitate  of  pyrophosphate,  it  may  be  dis- 
solved in  chlorhydric  acid,  and  after  neutralization  with  ammonia  and  the 
subsequent  addition  of  sodium  acetate  and  acetic  acid,  it  may  be  titrated 
with  a  standard  solution  of  uranium  acetate,  using  potassium  ferrocyanide 
as  indicator,  but  this  method  does  not  appear  to  offer  any  advantage. 

DETERMINATION  OF  SULPHUR  AND  SULPHURIC  ACID. 

The  accurate  determination  of  sulphur,  especially  when  it  exists  in  the 
sample  in  the  form  of  sulphide,  is  no  easy  matter.  It  is  essential  in  all 
the  methods  to  get  the  sulphur  into  solution  as  sulphate,  which  in  many 
cases  it  is  difficult  to  do;  the  effect  of  interfering  impurities  has  to  be 
carefully  guarded  against;  and  finally  it  is  doubtful  if  a  thoroughly  good 
volumetric  method  has  yet  been  devised,  in  the  absence  of  which  the  slow 
and  troublesome  details  of  gravimetric  analysis  have  to  be  performed.  Even 
in  the  case  of  the  shortest  methods  of  technical  analysis,  therefore,  with  their 
inherent  inaccuracies,  the  determination  of  sulphur  is  a  comparatively  slow 
and  tedious  process. 

GRAVIMETRIC  METHODS. — The  gravimetric  methods  for  the  estimation  of 
sulphur  are  based  upon  effecting  a  solution  as  sulphate  to  which  barium 
chloride  is  added,  throwing  down  barium  sulphate  which  is  filtered  off  and 
weighed  as  such.  The  decomposition  of  the  sulphides  is  effected  by  fusion 
with  alkaline  nitrates  or  potassium  hydrate  (Fahlberg-Iles  method) ;  or  by 
decomposition  with  acids  and  oxidizing  agents.  Among  the  latter  methods, 
decomposition  with  nitric  acid  and  potassium  chlorate  is  most  commonly 
employed;  aqua  regia  is  also  frequently  used,  although  it  is  apt  to  fail  to 
effect  complete  conversion  of  the  sulphur  into  sulphuric  acid ;  while  pyrites 
and  blende  may  be  decomposed  by  digestion  at  gentle  heat  with  water  and 
the  gradual  addition  of  bromine.  If  the  sulphides  have  been  prepared  in 
the  wet  way,  good  bromine  water  is  sufficient  to  oxidize  them. 

Fusion  with  Potassium  Hydrate. — This  method  is  doubtless  the  most 
accurate  of  the  technical  methods  for  the  determination  of  sulphur  in 
ores  and  furnace  products ;  it  also  requires  the  most  time.  In  this  method, 
one  or  two  sticks  of  potassium  hydrate,  which  must  be  free  from  sulphur, 


122  PRODUCTION    AND   PKOPEltTILS    OF    ZINC. 

are  fused  in  a  silver  crucible,  heated  by  a  spirit  lamp  (gas  must  not  be 
used).  When  the  alkali  is  in  quiet  fusion,  the  lamp  is  removed  and  the 
sample  (1  g.)  of  ore  is  introduced  and  the  fusion  is  then  continued  five  to 
30  minutes,  or  until  decomposition  is  complete.  The  fused  mass,  after  cool- 
ing, is  digested  in  a  beaker  with  warm  water,  which  is  boiled  after  the 
crucible  has  been  removed  and  is  then  filtered,  the  insoluble  matter  being 
washed  thoroughly  with  boiling  water.  From  20  to  40  c.c.  of  bromine 
water  are  added  to  the  filtrate,  which  is  then  heated  to  about  90°  C.  and 
acidified  with  chlorhydric  acid.  The  solution  must  next  be  evaporated  to 
dryness  to  render  silica  insoluble,  which  is  filtered  off  after  a  redigestion 
with  dilute  chlorhydric  acid  in  the  usual  manner.  The  filtrate  from  the 
silica  is  then  boiled  and  the  sulphur  is  precipitated  by  the  addition  of  a 
hot  solution  of  barium  chloride.  When  the  precipitation  is  effected  with 
boiling  hot  solutions,  the  barium  sulphate  comes  down  very  quickly  and  can 
be  filtered  off  rapidly  and  without  danger  that  it  will  run  through  the  paper. 
After  a  thorough  washing  the  precipitate  is  dried  and  transferred  into  a 
crucible  by  gently  rolling  the  paper  with  the  fingers,  the  paper  being  then 
burned  on  the  cover  of  the  crucible  and  its  ash  added  to  the  remainder  of  the 
precipitate..  After  ignition  the  precipitate  is  weighed  as  barium  sulphate, 
which  should  be  perfectly  white  in  color.  Unless  the  precaution  is  taken 
to  remove  silica  as  above  described  the  result  will  be  inaccurate,  but  if  that 
precaution  be  observed  this  method,  which  is  universal  in  its  application,  is 
entirely  satisfactory  in  all  respects  save  the  length  of  time  required. 

Digestion  with  Nitric  Acid. — This  method  is  not  so  accurate  as  that  in- 
volving the  fusion  with  potassium  hydrate,  but  is  much  more  rapid  and  is 
consequently  used  commonly  in  technical  laboratories.  As  described  by 
Furman  (op.  cit.,  p.  90)  it  is  performed  as  follows: 

Digest  1  g.  of  the  sample  in  a  flask  of  200  c.c.  capacity  with  3  to  4  g.  of 
potassium  chlorate  (in  the  case  of  a  heavy  sulphide  ore  more  potassium 
chlorate  should  be  used)  and  7  c.c.  of  nitric  acid,  about  3  c.c.  of  the 
acid  being  added  at  first  and  the  remainder  at  short  intervals,  1  c.c.  at  a 
time.  When  all  the  acid  has  been  added  heat  to  boiling  and  drive  off  all 
but  2  c.c.  The  solution  should  not  show  any  globules  of  yellow  sulphur, 
which  would  indicate  imperfect  oxidation. 

After  the  flask  has  cooled,  add  about  50  c.c.  of  water  and  then  an  excess  of 
saturated  solution  of  sodium  carbonate,  which  will  precipitate  the  lead, 
iron,  etc.,  and  decompose  the  sulphates  of  lead  and  calcium  which  have  been 
formed.  Boil  for  30  minutes  to  one  hour,  adding  water  to  keep  the  bulk  of 
the  solution  about  the  same.  Then  pass  through  a  fluted  filter  into  a  beaker, 
wash  until  no  traces  of  sulphuric  acid  are  shown,  acidify  the  filtrate  with 


ANALYSIS    OF    ZINC    ORES    AND    PRODUCTS.  123 

ohlorhydric  acid,  boil  to  expel  the  carbonic  acid  and  then  precipitate  with 
a  solution  of  barium  chloride,  proceeding  in  the  same  manner  as  described 
in  the  case  of  fusion  with  potassium  hydrate.  If  the  ore  contains  barium 
sulphate  the  latter  will  remain  undecomposed  with  the  precipitate  of  mixed 
carbonates. 

The  presence  of  nitric  acid  or  nitrates  is  objectionable  in  a  solution  which 
is  subsequently  to  be  precipitated  with  barium  chloride,  as  is  also  an  excess 
of  chlorhydric  acid.  Consequently  in  analyzing  blende  and  pyrites  some 
chemists  digest  0-5  g.  of  the  ore  with  10  c.c.  of  a  mixture  of  three  volumes 
of  nitric  acid  and  one  volume  of  chlorhydric,  heating  gently  at  intervals; 
then  evaporate  to  dryness,  treat  with  5  c.c.  of  chlorhydric  acid  and  evaporate 
again.  Take  up  with  1  c.c.  of  chlorhydric  acid  and  100  c.c.  of  hot  water, 
filter  and  wash.  Heat  the  filtrate,  make  slightly  alkaline  with  ammonia, 
filter  off  the  precipitated  ferric  hydrate,  wash  with  hot  water,  evaporate  to 
about  200  c.c.  if  necessary,  make  slightly  acid  with  HC1  and  add  the  barium 
chloride  solution. 

VOLUMETRIC  METHODS. — For  the  volumetric  estimation  of  sulphur  the 
latter  has  to  be  oxidized  and  dissolved  as  a  sulphate  in  the  same  way  as 
for  gravimetric  analysis.  The  aim  is  to  substitute  a  simple  titration  of  the 
solution  for  the  tedious  filtration  of  barium  sulphate  and  ignition  of  the 
precipitate.  Numerous  processes  have  been  devised,  but  none  has  been  gen- 
erally accepted  as  satisfactory.  This  subject  was  discussed  at  length  by  M. 
Felix  Marboutin  in  Moniteur  Scientifique  of  September,  1897,  to  which 
reference  should  be  made  by  those  who  are  particularly  interested  in  it. 
Description  will  be  limited  in  this  treatise  to  two  processes  which  seem  to  be 
most  particularly  adapted  to  the  requirements  of  technical  analysis. 

Furmans  Process. — H.  van  F.  Furman  has  proposed  a  volumetric 
method  for  the  determination  of  sulphur  which  is  based  on  Alexander's 
method  for  the  determination  of  lead  by  titration  with  a  standard  solution 
of  ammonium  molybdate.1  In  Alexander's  method  the  lead  is  precipitated 
as  sulphate,  wherefore  the  percentage  of  sulphur  can  be  calculated  from  the 
percentage  of  lead.  The  same  solution  of  ammonium  molybdate  may 
be  used  as  is  employed  for  the  estimation  of  lead,  or  a  special  solution  of  a 
strength  which  will  enable  the  percentage  of  sulphur  to  be  read  directly 
from  the  burette  may  be  prepared.  In  any  case  the  solution  will  be  standard- 
ized against  metallic  lead  or  lead  sulphate  in  the  same  manner  as  for  Alex- 
ander's method.  The  equivalent  in  sulphur  may  be  calculated  on  the  basis 
that  lead  sulphate  contains  10-56%  S. 

If  the  sulphur  of  the  sample  under  analysis  has  been  brought  into  solution 

1  Op.  cit.,  p.  92. 


124  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

by  fusion  with  caustic  potash  and  digestion  with  hot  water,  hydrogen 
peroxide  is  added  to  the  filtrate  to  oxidize  the  potassium  sulphide.  The 
solution  is  then  heated  and  acidified  with  a  slight  excess  of  nitric 
acid.  To  the  hot  solution  add  an  excess  of  a  solution  of  lead  nitrate  and 
filter,  retaining  as  much  as  possible  of  the  lead  sulphate  in  the  beaker.  Wash 
by  decantation  with  cold  water  until  a  reaction  for  lead  is  no  longer 
obtained.  Then  dissolve  the  lead  sulphate  in  hot  ammonium  acetate,  acidify 
with  acetic  acid  and  titrate  with  the  standard  ammonium  molybdate 
solution. 

In  case  the  sulphur  has  been  brought  into  solution  by  digestion  with 
nitric  acid  and  potassium  chlorate,  acidify  the  filtrate  from  the  precipitated 
carbonates  with  a  slight  excess  of  nitric  acid,  boil  out  the  carbonic  acid,  pre- 
cipitate the  sulphuric  acid  with  lead  nitrate  and  proceed  as  above. 

The  sulphur  may  also  be  put  into  solution  by  fusing  1  g.  of  the  sample 
with  10  g.  of  mixed  sodium  carbonate  and  potassium  nitrate.  Dissolve  the 
fused  mass,  when  cold,  in  hot  water.  Filter,  acidify  the  filtrate  with  nitric 
acid,  boil  to  drive  out  carbonic  acid,  precipitate  the  sulphuric  acid  with 
lead  nitrate  and  proceed  as  above. 

In  all  cases  the  reagents  used  should  be  carefully  examined  for  the  pres- 
ence of  sulphur. 

Andrews'  Process. — Max  Eeuter  considers1  that  of  all  methods  proposed 
for  the  estimation  of  combined  sulphuric  acid,  Andrews'  is  the  best,  and  if 
carried  out  exactly  as  described  its  accuracy  leaves  nothing  to  be  desired; 
moreover,  it  is  far  more  rapid  than  any  gravimetric  method  and  only  one 
standard  solution — viz.,  decinormal  sodium  thiosulphate — is  required,  which 
is  an  advantage  over  most  of  the  other  volumetric  methods. 

The  principle  of  this  method  is  as  follows :  From  a  boiling  solution  of  the 
sample  to  be  tested  in  which  the  sulphur  has  been  put  in  the  form  of  an 
alkali  sulphate  and  should  be  present  to  the  extent  of  about  0-07  g.  of  S0;?, 
the  sulphur  is  precipitated  by  an  excess  (150  c.c.)  of  barium  chromate  dis 
solved  in  chlorhydric  acid.    The  excess  of  the  acid  is  neutralized  by  boilin< 
with  ammonia  or  with  pure  powdered  chalk  (preferably  the  latter)  unti 
there  is  a  neutral  reaction,  the  precipitate  being  removed  by  filtration  am 
washed  with  hot  water.     After  cooling,  the  filtrate  which  contains  th< 
alkaline  chromate  corresponding  to  the  sulphate  in  the  solution  unde 
examination  is  acidulated  with  5  c.c.  (not  more)  of  strong  chlorhydric  acid, 
after  which  20  c.c.  of  a  10%  solution  of  potassium  iodide  are  added  ant 
the  liquid  is  allowed  to  remain  five  minutes  in  a  covered  beaker  to  insui 
complete  reduction  of  chromic  acid,  during  which  time  a  current  of  carboni( 

1  Chem.  Ztg.,  1808,  XXII,  357. 


ANALYSIS   OF   ZINC    ORES   AND   PRODUCTS.  125 

acid  is  passed  through  to  avoid  atmospheric  oxidation  of  the  iodohydric  acid 
set  free.  Finally  it  is  diluted  to  1  or  1-5  liters  and  titrated  quickly  with  the 
standard  thiosulphate  solution,  iodine  being  liberated  by  the  free  chromic 
acid.  The  reactions  are  represented  by  the  following  equations : 

2Na2S04+BaCr04=Na2Cr04-fBaS04. 

2Na2Cr04+2HCl=2NaCl+H20+  Na2Cr207. 

Na2Cr207+14HCl+6KI=:2CrCl34-6KCl-|-3I2+7H20. 

It  results  therefore  that  2  S03  corresponds  to  61;  or  l=V3  S03.  The 
following  solutions  are  required  for  the  analysis :  (1)  chlorhydric  acid  solu- 
tion of  3  to  4  g.  of  pure  barium  chromate,  which  is  prepared  by  precipitating 
potassium  chromate  with  barium  chloride  and  dissolving  the  washed  pre- 
cipitate in  30  c.c.  of  concentrated  chlorhydric  acid,  after  which  the  solution 
is  diluted  with  water  up  to  one  liter ;  change  in  the  degree  of  concentration 
ought  to  be  avoided ;  and  ( 2 )  a  decinormal  solution  of  sodium  thiosulphate. 

The  use  of  only  5  c.c.  of  chlorhydric  acid  before  the  titration  prevents  the 
reappearance  of  the  blue  coloration  after  the  titration  is  finished,  which 
occurs  if  as  much  as  20  c.c.  of  acid  be  used.  If  all  the  indicated  precautions 
are  observed  the  results  are  very  close.  A  dozen  analyses  can  be  made  easily 
in  an  afternoon.  Andrews'  process  was  described  originally  in  the  Ameri- 
can Chemical  Journal,  1880,  II,  567. 

SPECIAL  ANALYTICAL  METHODS. 

DETERMINATION  OF  ZINC  IN  ALLOYS. — A.  C.  Langmuir  in  the  Journal 
of  the  American  Chemical  Society,  XXI,  ii,  February,  1899,  described  the 
following  method  for  the  determination  of  zinc  in  alloys  containing  copper, 
tin,  lead,  iron  and  zinc :  Dissolve  in  nitric  acid,  evaporate  to  dryness,  and 
take  up  the  residue  with  nitric  acid  if  tin  be  present.  Filter  and  separate 
copper  and  lead  simultaneously  by  electrolysis.  The  solution  should  con- 
tain 5  to  10  c.c.  of  concentrated  nitric  acid  in  150  to  200  c.c.  of  water. 
After  removing  and  washing  the  electrodes  carrying  copper  and  lead,  the 
solution  is  evaporated  to  dryness  in  a  weighed  platinum  dish  and  the  residue 
ignited  and  weighed.  The  residue  is  then  treated  with  chlorhydric  acid, 
and  the  iron,  which  is  usually  small  in  amount,  is  precipitated  by  ammonia. 
The  precipitate  is  filtered  off,  ignited  and  weighed,  its  weight  being  deducted 
from  that  of  the  residue  (zinc  oxide)  weighed  in  the  platinum  dish.  If 
nickel  be  present  the  weight  of  the  combined  oxides  may  be  taken  and 
the  nickel  determined  subsequently,  the  weight  of  the  zinc  being  then  found 
bv  difference. 


120  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

ANALYSIS  OF  SPELTER. — In  making  a  chemical  examination  of  a  sample 
of  spelter  the  chief  consideration  is  the  percentages  of  various  impurities 
which  are  likely  to  be  present,  wherefore  it  is  customary  to  determine  them 
directly,  the  percentage  of  zinc  being  then  estimated  by  difference.  The 
impurities  which  are  generally  to  be  looked  for  are  lead,  iron  and  cadmium ; 
less  frequently,  arsenic,  tin,  and  copper.  In  making  an  analysis  of  spelter 
it  is  advisable  to  weigh  out  a  comparatively  large  quantity,  say  10  or  20  g., 
so  that  results  may  be  reported  to  at  least  three  places  of  decimals. 

Lead  in  spelter  is  conveniently  determined  by  dissolving  10  g.  of  the 
sample  in  100  c.c.  of  dilute  chlorhydric  acid  (1:2),  without  heating,  and 
decanting  off  the  solution  before  the  zinc  is  entirely  taken  up.  The  re- 
mainder is  then  dissolved  in  2  c.c.  of  dilute  nitric  acid  and  the  solution 
is  evaporated  until  most  of  the  acid  is  removed,  after  which  it  is  diluted 
with  water  to  about  30  c.c.  and  filtered  off.  The  lead  is  then  precipitated 
as  sulphate  by  the  addition  of  10  c.c.  of  dilute  sulphuric  acid.  The  pre- 
cipitate of  lead  sulphate  may  be  filtered  off  and  weighed  as  such,  or  it  may 
be  redissolved  and  titrated  with  ammonium  molyhdate.  The  filtrate  from 
the  lead  sulphate,  including  the  original  solution  decanted  off,  may  be 
used  for  the  determination  of  iron,  the  latter  being  precipitated  as  hydroxide 
by  oxidizing  the  solution  with  a  little  bromine  water  and  then  adding  40  c.c. 
of  ammonia  water  of  0-925  sp.  gr.  A  systematic  determination  of  all  of  the 
common  impurities  of  spelter  is  provided  for  in  the  following  scheme. 

Tin. — The  weighed  sample  is  dissolved  in  dilute  nitric  acid,  boiled  and 
allowed  to  settle  if  there  be  formed  a  white  insoluble  substance.  In  the 
case  of  the  latter  it  should  be  filtered  off,  washed,  dried  and  weighed,  this 
being  oxide  of  tin. 

Lead. — To  the  filtrate  or  the  original  clear  solution  add  ammonia  water 
and  ammonium  carbonate,  boil,  filter  off  the  precipitate,  wash  with  "hot 
water,  digest  the  precipitate  with  dilute  sulphuric  acid,  filter,  wash  and 
weigh  as  lead  sulphate,  from  which  the  percentage  of  lead  may  be  calculated. 

Iron. — Make  alkaline  with  ammonia  the  filtrate  from  the  lead  sulphat 
and  pass  hydrogen  sulphide  through  it.  Filter  off  the  precipitate  and  dii 
solve  in  chlorhydric  acid,  oxidize  with  nitric  acid  and  precipitate  again  wit! 
ammonia.  Wash,  ignite  and  weigh  as  ferric  oxide.  Instead  of  weighing 
the  ferric  oxide,  the  percentage  of  iron  may  be  determined  by  titration  wit! 
potassium  permanganate  in  the  usual  manner. 

Arsenic. — To  the  filtrate  from  the  sulphide  of  iron  add  chlorhydric  aci< 
in  slight  excess,  filter  off  and  wash  the  precipitate;  rinse  it  back  into  th( 
beaker,  dissolve  in  nitric  acid,  filter  off  the  sulphur  and  add  ammonia 
excess  and  magnesia  mixture.  Filter  off  the  ammonium-magnesium  arsenal 


ANALYSIS    OF    ZINC    ORES    AND    PRODUCTS.  1-7 


and  wash  with  dilute  ammonia.  Dry,  ignite  with  nitric  acid  and  weigh  as 
magnesium  pyrarsenate,  from  which  the  percentage  of  arsenic  may  be  cal- 
culated, on  the  basis  that  magnesium  pyrarsenate  (Mg2As207)  contains 
484%  As.  The  magnesia  mixture  is  prepared  by  dissolving  22  g.  of  mag- 
nesia in  about  250  c.c.  of  dilute  chlorhydric  acid,  then  adding  5  g.  more 
of  magnesia,  boiling  and  filtering;  to  the  filtrate,  300  g.  of  ammonium 
chloride  and  250  c.c.  of  strong  ammonia  are  added,  and  the  solution  is  then, 
diluted  with  water  to  2,000  c.c. 

Copper. — To  the  filtrate  from  the  ammonia  and  ammonium  carbonate 
add  sulphuric  acid  in  small  excess  and  treat  with  hydrogen  sulphide.  Filter 
off  the  precipitate,  wash  and  rinse  it  into  a  beaker;  then  boil  with  dilute 
sulphuric  acid  and  filter,  saving  the  filtrate.  Dry,  burn  the  filter  paper 
with  the  precipitate,  treat  with  a  drop  or  two  of  nitric  acid,  ignite  and 
weigh  as  copper  oxide  (CuO). 

Cadmium. — To  the  filtrate  from  the  sulphide  of  copper  add  ammonia 
so  as  nearly  to  neutralize  the  excess  of  acid  and  treat  with  hydrogen  sul- 
phide. Filter  off  the  precipitate,  using  a  weighed  filter,  wash  first  with  an 
acid  solution  of  hydrogen  sulphide  and  afterward  with  water,  dry  at 
100°  C.  and  weigh  as  cadmium  sulphide;  if  free  sulphur  is  suspected  to  be 
present,  wash  with  carbon  bisulphide  before  drying.1 

Zinc. — Although  the  percentage  of  zinc  in  pure  spelters  is  best  determined 
by  difference  as  described  above,  according  to  A.  C.  Langmuir  in  the  Journal 
of  the  American  Chemical  Society,  XXI,  ii,  February,  1899,  in  the  case  of 
impure  spelters  it  is  sometimes  more  convenient  and  equally  accurate  to 
determine  the  zinc  directly.  A  convenient  method  is  the  following:  Dis- 
solve 0-5  g.  of  the  sample  in  nitric  acid  and  separate  the  lead  electrolytically 
in  a  solution  containing  10%  nitric  acid.  A  platinum  cylinder  should  be 
used  in  order  to  collect  the  lead  peroxide.  The  solution  is  then  evaporated 
to  dryness  in  a  weighed  platinum  dish,  and  the  residue  ignited  and  weighed. 
Then  dissolve  in  a  little  chlorhydric  acid,  reduce  with  two  or  three  grams 
of  granulated  zinc,  add  sulphuric  acid  to  complete  the  reaction,  dilute  to 
one  liter  with  ice  water  and  titrate  with  potassium  permanganate.  The 
weight  of  the  iron  found  is  then  deducted  from  the  weight  of  the  residue 
in  the  dish.  If  cadmium,  arsenic  or  other  impurities  be  present  in  the 
spelter  in  more  than  traces,  the  above  method  is  inapplicable  unless  modified 
to  include  treatment  by  hydrogen  sulphide. 

Doctor  Langmuir  in  a  paper  read  before  the  Xew  York  Section  of  the 
American  Chemical  Society,  March  18,  1901,  described  a  short  method  for 
the  analysis  of  spelter,  substantially  as  follows:  "Cover  the  weighed 

:  C.  and  J.  J.  Beringer,  Textbook  of  Assaying,  p.  224. 


128  PRODUCTION  AND  PROPERTIES  OE  ZINC. 

quantity  of  spelter  with  water,  add  a  few  drops  of  platinic  chloride,  and 
then  sufficient  sulphuric  acid  to  start  a  moderate  rate  of  solution.  The 
zinc  dissolves,  leaving  lead  in  the  metallic  state.  Filter,  dissolve  the  lead 
in  nitric  acid  on  the  filter  and  convert  to  sulphate,  as  usual.  The  solution 
of  zinc  may  then  be  at  once  titrated  for  iron  by  permanganate  solution,  after 
which  cadmium  is  precipitated  by  hydrogen  sulphide.7' 

VALUATION  OF  ZINC-DUST. — The  commercial  value  of  this  material  de- 
pends upon  the  percentage  of  metallic  zinc  which  it  contains.  Inasmuch  as 
it  invariably  contains  zinc  oxide  also,  the  ordinary  methods  for  the  estima- 
tion of  zinc  are  inapplicable,  since  they  give  only  the  total  zinc.  There  are 
numerous  methods  described  for  the  determination  of  metallic  zinc  in  this 
material,  most  of  which  depend  upon  the  measurement  of  the  hydrogen 
evolved  by  a  treatment  of  the  sample  with  acid,  comparing  the  quantity 
with  that  given  off  by  a  corresponding  weight  of  pure  zinc.  Other  methods 
depend  upon  the  measurement  of  the  reducing  power  of  the  metallic  zinc  in 
the  dust.  One  of  the  best  methods  for  the  valuation  of  zinc  dust  is  con- 
sidered to  be  that  which  has  been  described  by  Klemp.1 

Klemp's  method  depends  on  the  power  of  zinc  to  reduce  potassium  iodate 
to  iodide  in  an  alkaline  solution.    When  the  solution  is  afterward  acidified, 
iodine  is  liberated  and  is  distilled  off  from  the  mixture  into  potassium 
iodide  solution,  and  titrated  with  sodium  thiosulphate.     From  0-5  to  1  g. 
of  the  sample  is  weighed  out  into  a  200  c.c.  stoppered  flask.     For  every 
0-1  g.  of  zinc  present,  10  c.c.  of  a  solution  containing  370  g.  of  potassium 
hydroxide,  or  300  g.  of  sodium  hydroxide  per  liter,  and  3  c.c.  of  a  solution 
containing  15-25  g.  of  potassium  iodide  per  300  c.c.  are  measured  into  a 
beaker,  and  then  poured  into  the  flask.     Some  glass  beads  are  added,  and 
the  flask  stoppered  and  shaken  for  five  minutes  in  the  cold,  no  advantage 
being  gained  by  heating  it.     Its  contents  are  then  washed  into  a  250  or 
500  c.c.  flask,  and  made  up  to  the  mark  with  water,  from  which  100  c.c. 
are  transferred  into  the  retort  of  a  Topf's  apparatus,  dilute  sulphuric  aci( 
is  added,  and  the  apparatus  filled  with  carbon  dioxide.    A  solution  of  potas 
sium  iodide  is  placed  in  the  receiver,  and  the  retort  heated,  at  first  gently 
and  then  more  strongly  till  the  contents  are  perfectly  colorless, 
stream  of  carbon  dioxide  is  continued  throughout  the  distillation,  whic 
generally  occupies  about  20  minutes.    The  solution  of  iodine  in  potassiui 
iodide  is  then  transferred  from  the  receiver  into  a  flask,  and  standard  solu- 
tion of  sodium  thiosulphate  is  added  in  slight  excess ;  the  excess  is  titratt 
with  weak  standard  iodine  solution,  starch  being  used  as  an  indicator.    Aftei 
correcting  for  the  excess,  the  quantity  of  zinc  is   calculated  from  tht 

1  Zts.  f.  analyt.  Chemie,  XXIX,  253. 


ANALYSIS   OF   ZINC    ORES   AND   PRODUCTS.  121) 


quantity  of  thiosulphate  used.  Each  0-2  g.  of  iodine  found  corresponds  to 
0-25644  g.  of  zinc.  Iron  and  lead  do  not  interfere  materially  with  the 
method,,  though  results  are  a  little  lower  in  the  presence  of  those  metals. 
The  results  by  this  method  agree  well  with  those  obtained  by  that  of 
Fresenius,  but  are  generally  higher  than  those  obtained  by  Drewson's  and 
lower  than  those  obtained  by  Topf  s  method  (vide  Journ.  Soc.  Chem.  Ind., 
IX,  968).  For  a  volumetric  method,  depending  on  the  amount  of  hydrogen 
evolved  by  the  action  of  an  acid  on  zinc-dust,  vide  Journ.  Soc.  Chem.  Ind., 
V,  145. 

Another  method  consists  in  the  treatment  of  the  sample  with  a  definite 
quantity  of  a  standard  solution  of  potassium  chromate  or  bichromate,  an 
excess  of  which  is  employed,  and  then  adding  an  excess  of  dilute  sulphuric 
acid.  The  reaction  is  expressed  as  follows: 


Wl 


3Zn+2Cr03+6H2S04=3ZnS04+Cr2(S04)s+6H20. 


rhen  the  solution  of  the  zinc  is  complete,  the  excess  of  chromate  em- 
ployed is  determined  by  titration  with  a  standard  solution  of  ferrous  sul- 
phate. 

The  following  method  is  due  to  A.  Fraenkel :  About  1  g.  of  the  sample 
is  weighed  into  a  dry,  well-stoppered  flask  of  200  c.c.  capacity,  and  treated 
with  100  c.c.  of  a  semi-normal  solution  of  potassium  bichromate  and  10  c.c. 
of  dilute  sulphuric  acid  (1 :  3).  The  mixture  is  shaken  for  five  minutes,  then 
10  c.c.  more  of  the  acid  are  added,  and  the  mixture  is  again  shaken  for  from 
10  to  15  minutes.  The  zinc  by  this  time  will  have  entirely  dissolved.  The 
solution  is  transferred  to  a  half-liter  flask  and  diluted  to  the  mark,  50  c.c. 
of  it  are  taken  and  after  the  addition  of  10  c.c.  of  potassium  iodide  solution 
(1:10)  and  5  c.c.  of  sulphuric  acid  is  titrated  with  decinormal  sodium 
thiosulphate  solution.1 

A  simple  method  described  by  A.  B.  Wahl  consists  in  treating  0-5  g.  of 
the  sample  with  25  c.c.  of  cold  water  in  a  250  c.c.  stoppered  flask,  and  after 
suspending  the  dust  by  a  thorough  shaking  7  g.  of  ferric  sulphate  are  added. 
The  following  reaction  takes  place  : 

Fe2  ( S04)  3+Zn=ZnS04+  2FeS04. 

There  is  a  gentle  evolution  of  heat,  and  after  shaking  the  flask  about  15 
minutes  the  zinc  will  be  completely  dissolved,  the  residue  consisting  of  im- 
purities. Strong  sulphuric  acid  (about  25  c.c.)  is  then  added  and  the  flask 
is  filled  with  water  up  to  250  c.c.,  of  which  50  c.c.  are  tiken  and  further 

1  Mitt,  des  k.  k.  techn.  Gewerbe  Museums  in  Wien,  1900,  X,  161. 


130  PRODUCTION    AND   PROPERTIES    OF    Z1XC. 

diluted  to  100  c.c.  and  then  titrated  with  standard  potassium  permanganate, 
which  measures  the  quantity  of  ferrous  salt  reduced  by  the  zinc  and  there- 
fore the  percentage  of  the  latter  in  the  sample.1 

DETERMINATION  OF  SULPHATES  AND  SULPHIDES. — It  is  frequently  de- 
sirable to  determine  the  relative  proportion  of  sulphur  which  exists  as  sul- 
phide and  various  sulphates  especially  in  roasted  ore.  An  estimation  which 
is  sufficiently  correct  for  most  technical  purposes  can  be  made  in  a  simple 
manner.  The  neutral  sulphate  of  zinc,  iron  and  most  of  the  other  metals, 
including  magnesium,  which  are  likely  to  be  met  with  in  zinkiferous  ores 
are  readily  soluble  in  cold  water,  wherefore  they  may  be  removed  by  a  simple 
leaching  with  water'.  It  is  preferable  not  to  boil  the  solution,  since  thereby 
basic  sulphates  are  likely  to  be  precipitated.  After  removal  of  the  soluble 
sulphates,  the  sulphuric  anhydride  existing  ,in  the  form  of  lead  sulphate 
and  the  basic  sulphates  can  be  extracted  by  boiling  with  a  solution  of  sodium 
acetate ;  or  in  case  there  be  no  necessity  to  determine  separately  the  soluble 
sulphates,  the  sample  may  be  treated  directly  with  sodium  acetate. 

In  examining  a  sample  of  roasted  blende  to  determine  the  proportion  of 
sulphur  existing  as  sulphide  and  sulphates,  boil  1  g.  in  a  200  c.c.  flask  with 
50  c.c.  of  a  5%  solution  of  sodium  acetate;  allow  to  settle  and  decant  the 
solution  through  a  filter;  repeat  the  treatment  with  sodium  acetate  and 
then  boil  twice  with  distilled  water.  The  sulphur  occurring  as  sulphates 
will  then  be  in  the  filtrate,  while  the  sulphur  as  sulphide  will  be  in  the  resi- 
due remaining  on  the  filter.  The  former  may  be  precipitated  with  barium 
chloride  in  the  usual  manner,  care  being  taken  to  remove  interfering  impuri- 
ties. The  residue  on  the  filter  may  be  washed  into  a  flask  and  treated  with 
nitric  acid  and  potassium  chlorate  to  effect  decomposition  of  the  sulphides 
in  the  usual  manner. 

Steinbeck's  method  for  the  determination  of  basic  sulphates  consists  of 
the  addition  to  the  residue,  remaining  after  removal  of  the  sulphates  soluble 
in  water,  of  three  times  its  weight  of  sodium  bicarbonate  and  enough  water 
to  dissolve  most  of  the  soda,  This  is  allowed  to  stand  for  24  hours  with 
occasional  shaking.  The  solution  is  then  filtered  off,  acidified  with  chlor- 
hydric  acid,  boiled  to  remove  the  carbon  dioxide  and  finally  precipitated  with 
barium  chloride.  Sodium  bicarbonate  in  solution  reacts  with  all  the  basic 
sulphates  and  with  lead  sulphate,  while  it  has  no  effect  upon  the  sulphides. 
Calcium  sulphate  is  decomposed  by  it,  but  barium  sulphate  is  not. 

DETERMINATION  or  SULPHUROUS  ACID  IN  BOASTING-FURNACE  GAS. — In 
works  where  the  sulphurous  gas  from  the  roasting  furnaces  is  utilized  for 
the  manufacture  of  sulphuric  acid  it  is  important  to  control  the  process 

1  Journ.  Soc.  Chem.  Ind.,  XVI,  15. 


ANALYSIS    OF    ZINC    ORES    AND    PRODUCTS. 


131 


determining  the  percentage  of  sulphurous  anhydride  by  volume  in  the  gas. 
The  following  method  is  described  by  Mr.  F.  J.  Falding:1  The  sample  of 
the  gas  is  most  conveniently  taken  through  a  1-in.  pipe  projecting  into  the 
flue  leading  to  the  Glover  tower.  The  1-in.  pipe  should  be  built  into  the 
wall  of  the  flue.  On  the  outside  it  is  reduced  to  14  in.,  the  complete 
arrangement  being  shown  in  the  accompanying  engraving.  The  rubber  tube 
should  be  of  sufficient  length  to  permit  considerable  freedom  of  movement. 
It  connects  with  a  bent  Vie-in-  glass  tube,  of  which  one  leg  passes  through 
the  rubber  stopper  of  an  8-oz.  bottle  of  white  glass.  Another  bent. glass 
tube  with  equal  legs  is  inserted  through  the  other  hole  of  the  stopper 
and  connected  by  a  i^-in.  tube  with  a  4-qt.  bottle  as  shown.  The  rubber 


FIG.  8. — APPARATUS  FOR  THE  DETERMINATION  OF  SULPHUROUS  ACID. 

tube  leading  from  the  4-qt.  bottle  terminates  with  a  piece  of  glass  tubing 
drawn  down  to  about  Vie  to  %  in.,  which  must  be  long  enough  to  reach 
about  2  in.  inside  of  a  250  c.c.  graduated  jar. 

In  order  to  make  the  determination  a  solution  of  starch  and  a  deci- 
normal  solution  of  iodine  are  required.  These  should  be  prepared  as 
directed  in  Lunge  and  Hurter's  Alkali  Makers  Handbook,  second  edition,  p. 
171.  The  iodine  solution  will  keep  well  in  a  dark,  cool  place.  The  starch 
solution  is  more  likely  to  spoil,  even  when  saturated  with  salt,  and  should 
be  renewed  more  frequently. 

In  operation  the  large  bottle  is  filled  with  water,  care  being  taken  to  make 

1  The  Mineral  Industry.  VII.  698. 


132  PRODUCTION    AND   PROPERTIES    OF   ZINC. 

the  stopper  perfectly  tight.  The  siphon  is  started  by  a  slight  suction 
through  the  nozzle  and  the  pinch-cock  is  then  closed.  The  8-oz.  bottle  is 
filled  about  one-fourth  full  of  clean  water,  slightly  warmed  in  winter,  into 
which  about  a  teaspoonful  of  starch  solution  is  poured.  Then  by  means  of 
a  pipette  10  c.c.  of  iodine  solution  is  added  to  the  contents  of  the  8-oz.  bottle. 
The  rubber  stopper  is  then  replaced  tightly  and  the  pinch-cock  between 
the  flue  and  the  small  bottle  is  closed.  The  pinch-cock  at  the  nozzle  is  then 
opened,  allowing  the  water  to  waste.  When  the  water  ceases  to  run,  proving 
the  tightness  of  the  stoppers  and  connections  throughout  the  apparatus, 
the  pinch-cock  between  the  flue  and  the  small  bottle  is  opened.  Then  take  the 
small  bottle  in  the  left  hand,  keeping  the  right  hand  on  the  pinch-cock  at 
the  nozzle,  and  shake  the  small  bottle,  not  too  violently,  holding  it  to  the 
light  in  such  a  way  that  any  change  in  color  can  be  readily  noted.  When 
a  considerable  change  occurs  in  the  color  stop  the  flow  of  water  with  the 
right  hand,  and  close  the  pinch-cock  on  the  tube  between  the  flue  and  the 
small  bottle.  The  tube  between  the  flue  and  the  pinch-cock  is  now  filled 
with  the  gas  to  be  tested.  Remove  the  stopper  from  the  small  bottle  and 
add  10  c.c.  of  the  iodine  solution.  Replace  the  cork  tightly.  Open  the  pinch- 
cock  between  the  flue  and  the  small  bottle.  Then  with  the  pinch-cock  at 
the  nozzle  in  the  right  hand  carefully  waste  water  until  the  liquid  in  the 
glass  tube,  terminating  the  tube  from  the  flue,  is  depressed  to  the  bottom ; 
or,  in  other  words,  until  the  tube  is  filled  with  the  gas  to  its  extreme  end. 
Just  before  the  first  bubble  of  gas  would  escape  and  pass  through  the 
solution  allow  the  water  to  commence  running  into  the  graduated  jar. 
Shake  the  bottle  as  before  and  stop  the  water  running  the  instant  the 
color  is  discharged.  The  number  of  cubic  centimeters  of  water  the  jar 
holds  at  the  exact  point  of  the  discharge  of  color  from  the  small  bottle  rep- 
resents the  percentage  by  volume  of  S02  in  the  burner  gas. 

Before  making  further  tests  the  small  bottle  should  be  emptied  and  fresh 
water  and  starch  solution  used.  Any  intelligent  workman  can  be  taught  to 
make  the  test,  and  after  a  little  practice  can  perform  a  test  in  less  than 
three  minutes.  He  may  either  be  provided  with  a  percentage  table  or 
instructed  to  keep  his  gas  between  128  and  138  c.c.,  or  as  may  be  required. 
The  following  table  is  useful  for  reference : 


c.  c.  water  in  jar  
%  SOa  by  volume.  .  .  . 

82 
12-0 

86 
11-5 

90 
11-0 

95 
10'5 

100 
10  '0 

106 
9'5 

113 
9'0 

120 
8-5 

128 
8-0 

138 
7'5 

148 
7-0 

160 
7'5 

175 
6-0 

192 
5'5 

212 
5-0 

VI 

PROPERTIES  OP  ZINC  AND  ITS  ALLOYS. 

Zinc  is  a  bluish-white  metal  of  shining  luster,  which  according  to  the 
periodic  arrangement  of  the  elements  by  Mendeleef  is  classified  in  group 
II,  corresponding  to  the  symbol  RO,  the  series  in  the  order  of  atomic  weights 
consisting  of  beryllium  (9-1),  magnesium  (24-36),  calcium  (40),  zinc 
(65-4), strontium  (87-68), cadmium  (112-3), barium  (137-43), erbium  (166) 
and  mercury  (200).  Of  these  elements,  magnesium,  zinc  and  cadmium  have 
remarkable  points  of  resemblance  in  their  chemical  and  physical  properties, 
while  three  others,  viz.,  calcium,  strontium  and  barium  (alternating  with 
magnesium,  zinc  and  cadmium  in  the  periodic  arrangement)  present  an 
equally  striking  similarity.  Beryllium  and  mercury  are  both  volatile  metals. 
Erbium  has  not  yet  been  isolated  in  its  elemental  form,  and  its  position  in 
Mendeleef 's  classification  is  doubtful.  An  arrangement  of  these  elements  in 
a  form  which  more  clearly  shows  their  connection,  was  given  by  Professor 
T.  W.  Richards  in  the  Proceedings  of  the  American  Academy  of  Arts  and 
Sciences,  March  9,  1898,  and  the  American  Chemical  Journal,  1898, 
XX,  vii,  as  follows : 

(   Ca(40'0)  :  Sr  (87-68)  :Ba(137'43): 

H(1-0075H  Be(9-l)  ]  Mg(24-36)  } 

(   Zn  (65-4) :  Cd(112'3) : :  Hg(200) 

Atomic  Weight. — The  atomic  weight  of  zinc  was  formerly  supposed  to 
be  65  (vide  Remsen,  Eliot  &  Storer  et  al.)  and  that  figure  is  commonly 
used  at  present,  but  later  investigation  has  shown  it  to  be  about  65-4.  P.  W. 
Clarke  adopts  65-41 ;  T.  W.  Richards,  65-40 ;  and  the  revising  commission  of 
the  German  Chemical  Society,  65-4.  Inasmuch  as  the  solutions  employed  in 
the  volumetric  estimation  of  zinc  are  commonly  standardized  against  zinc 
oxide,  while  in  gravimetric  analysis  the  metal  is  weighed  as  ZnO,  it  makes 
a  slight  difference  whether  the  atomic  weight  of  zinc  be  assumed  as  65  or 
654. 1  The  atomic  volume  of  zinc  is  9-1.  In  its  chemical  relations  it  is 

1  For  example  :  If  the  atomic  weights  of  oxide  is  80-344 ;  if  the  atomic  weights  be 
oxygen  and  zinc  be  reckoned  16  and  65-4  re-  reckoned  16  and  65,  the  percentage  is 
spectively,  the  percentage  of  zinc  in  zinc  80-247.  If  one  gram  of  a  sample  yields 

133 


134  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

bivalent,  combining  with  two  atoms  of  chlorine  and  one  atom  of  oxygen, 
forming  chlorides  and  oxides  which  are  analogous  to  those  of  magnesium 
and  cadmium. 

PHYSICAL  PROPERTIES. — The  specific  gravity  of  cast  zinc  is  6-861  accord- 
ing to  Brisson,  6-9154  according  to  Karsten,  and  7-149  according  to 
Matthiessen.  According  to  Bolley  the  specific  gravity  of  the  metal  when 
poured  at  or  near  its  melting  point  and  cooled  slowly,  is  7445,  and  according 
to  Rammelsberg,  7-128;  when  poured  at  red  heat  and  cooled  slowly,  7-120 
according  to  Bolley,  and  7-101  according  to  Rammelsberg;  when  poured  at 
the  melting  point  and  cooled  quickly,  7-158  (Bolley)  and  7-147  (Rammels- 
berg) ;  poured  at  red  heat  and  cooled  quickly,  7-109  (Bolley)  and  7-037 
(Rammelsberg).  By  rolling,  the  specific  gravity  of  zinc  is  increased  to 
7-2  or  7-3. 

Melting,  Boiling  and  Ignition  Points. — Zinc  melts  at  410°  C.  according 
to  Wurtz,  at  412°  according  to  Daniell,  at  415°  according  to  Roberts-Austen, 
at  419°  C.  according  to  Heycock  and  Neville,  and  at  433°  according  to 
Person.  Becquerel  gives  its  boiling  point  as  891°  C.;  Violle,  929-6°; 
F.  Meier  and  Crafts,  940°  C. ;  Roberts-Austen,  940°  ;  Thum,  1,000°;  Deville 
and  Troost,  1,040° ;  Komorek,  1,050°.  These  differences  are  due  probably 
to  inaccuracies  in  the  determinations,  the  older  observers  not  having  the 
advantages  of  recent  pyrometry.  At  all  events  the  boiling  point  of  zinc  is 
lower  than  the  melting  point  of  silver  (which  is  given  as  970°  C.  by  Holman, 
Lawrence  and  Barr,  in  the  Technology  Quarterly,  1896,  IX,  24  to  39),  since 
silver  does  not  melt  in  zinc  vapor.1  According  to  Barus2  the  boiling  point 
of  zinc  is  raised  1-5°  C.  for  each  centimeter  of  atmospheric  pressure  above 
760  mm.  The  fluid  density  of  zinc  is  6-550  by  Mallet's  method,  and  6-480 
by  oncosimeter.  The  specific  gravity  of  zinc  vapor  is  2-36  (V.  Meyer, 

750  mg.  of  ZnO  by  weight  or  by  tltratlon.  thermo-couple     contained     In     a     porcelain 

the  percentage  of  zinc  in  the  ore  according  Rose's  tube,  sealed  a  I  the  end  and  Inserted 

to    the    former    constants    is    60-258 ;     ac-  through   the   cover   of   the   crucible,   which 

cording  to  the  latter,  60-185;  this  is  a  dif-  was   fitted  besides   with  tubes  by  which  a 

ference  of  1-46  Ib.  of  metal  in  2,000  Ib.  of  current  of  nitrogen  could  be  passed  through, 

ore  of  that  grade.  The  temperature  was  maintained  2°  or  3° 

1  Since  the  above  was  written  the  boiling  below  the  boiling  point  of  the  metal  until 

point  of  zinc  has  been  determined  accurate-  the   latter   was    heated    uniformly ;    it   was 

ly  by  D.   Berthelot    (vide  Comptes  Rendus,  then  raised  slowly  to  the  boiling  point,  at 

CXXXI,  vi,380  to  382,  and  Journ.  Soc.  Chem.  which  it  remained  steady  in  spite  of  further 

Ind.,    Oct.    31,    1900).     The    molten    metal  increase  in  the  electric  current.     Five  deter- 

was  contained  in  a  deep,  narrow  porcelain  minations   gave   results   varying  from   913° 

crucible,  surrounded  by  a  nickel  wire,  which  to  927°  C.,  thus  checking  closely  the  figure 

when    traversed     by     an     electric     current  of  Violle  and  completely  discrediting  the  old 

formed  the  source  of  heat,   the  whole   ap-  figures  of  1,000°  C.  and  upward, 

paratus    being    packed    in     magnesia     and  a  Die    Physikalische   Behandlung   und   die 

asbestos    to    prevent    radiation.     The    tern-  Messung  hoher  Temperaturen,  p.  42. 
perature   was   measured    by    means    of    a 


PROPERTIES    OF    ZINC    AXD    ITS    ALLOYS.  135 

Berichte  der  deutschen  Chemischen  Gesellschaft,  1886,  XIX,  3295).  One 
liter  of  zinc  vapor  weighs  32-7  criths1  (Frankland  and  Japp,  Inorganic 
Chemistry,  London,  1884,  p.  582).  Upon  cooling  below  the  boiling 
point  zinc  vapor  condenses  to  liquid,  the  more  easily  the  less  the  vapor  is 
mixed  with  other  gas;  if  the  vapor  be  cooled,  however,  below  the  melting 
point  of  the  metal  it  is  condensed  directly  in  the  solid  form  as  a  fine  blue 
powder.  This  property  plays  an  important  part  in  the  practical  metallurgy 
of  zinc.  In  melting  zinc,  the  increase  in  volume  in  the  change  from  the 
cold,  solid  state  to  the  liquid  is  1140%.  Between  0°  and  100°  C.  the 
specific  heat  of  zinc  is  0-09555  (Regnault) ;  other  authorities  give  it  as 
0-0927  from  0°  to  100°  C.  and  04015  from  100°  to  300°  C. 

Zinc  burns  in  the  air  at  a  temperature  as  low  as  500°  C.  (according 
to  Daniell  at  505°)  with  a  bright,  greenish- white  flame  and  the  formation 
of  oxide,  ZnO.  Such  fine  shavings  as  are  employed  for  the  precipitation  of 
gold  from  cyanide  solutions  may  be  ignited  with  a  lucifer  match  and  burn 
almost  as  freely  as  straw.  Zinc  in  an  extremely  finely  divided  form,  such  as 
commercial  "zinc  dust,"  is  subject  to  such  rapid  oxidation  that  it  is  liable  to 
spontaneous  combustion  and  even  to  explosion ;  it  is  classed  by  fire  under- 
writers as  a  dangerous  substance.  When  heated  in  chlorine,  or  the  vapors  of 
bromine  or  iodine,  zinc  burns  brilliantly,  with  the  formation  of  chloride, 
bromide  or  iodide  respectively. 

Crystallization. — Zinc  crystallizes  in  rhombohedral  forms  of  the  hexagonal 
system  and  may  be  obtained  in  those  forms  by  heating  to  the  melting  point, 
but  not  higher,  and  pouring  upon  a  non-conducting,  cold  surface.  Dana 
notes  that  it  also  appears  to  crystallize  in  the  isometric  system,  at  least  in 
various  alloys.  Ordinarily,  however,  the  metal  has  a  coarsely  laminar  tex- 
ture, sometimes  granular.  The  fracture  is  granular  or  coarsely  crystalline, 
dependent  upon  the  temperature  of  casting,  being  coarse  when  the  metal  is 
heated  nearly  to  redness  before  pouring  and  fine  when  the  temperature  of 
the  liquid  metal  is  not  much  above  its  melting  point.  Zinc  heated  to  160° 
C.  emits  when  bent  a  cry  like  tin,  but  not  so  loud,  which  is  supposed  to  be 
due  to  the  sliding  of  the  crystal  faces  over  one  another. 

Ductility,  Malleability  and  Hardness. — At  ordinary  temperatures  zinc  is 
brittle,  especially  when  impure,2  but  between  100°  C.  and  150°  C.  it  becomes 

1  The  crith  is  the  weight  of  one  liter  of  of  these  anomalous   facts   is   found   in   the 
hydrogen  at  0°  C.  and  760  mm.  atmospheric  observations    of    Gustav    Rose    and    others 
pressure=0-0896  g.  that  much  depends  upon  the  system  of  cry s- 

2  Impure  commercial  zinc  may  frequently  tallization.     "Supposing  a   mass   of  molten 
be  broken  in  the  direction  of  its  cleavage  zinc  to  freeze  into,  say,  cubes,  the  ingot  will 
faces    by    repated    blows    with    a    hammer.  be  ductile ;  an  ingot  of,  say,   rhombohedra, 
According  to  some  authorities  pure  zinc  al-  on  the  other   hand  is   almost  bound   to  be 
ways  yields  ductile  ingots.     A  clue  to  some  brittle,  because  the  crystals  are  oriented  in 


136  PRODUCTION   AND   PROPERTIES   OF   ZINC. 

so  malleable  and  ductile  that  it  may  be  rolled  into  sheets  and  drawn  into 
wire,  and  after  cooling  retains  those  properties,  which  important  discovery 
was  made  by  Hobson  and  Sylvester  in  1805. 1  But  at  205°  C.,  it  becomes  so 
brittle  again  that  it  may  be  powdered  in  a  mortar.  When  cast  at  a 
temperature  near  the  melting  point  it  is  more  malleable  than 
when  cast  at  a  higher  temperature,  and  is  also  less  acted  upon  by  acids 
(Percy).  In  malleability  zinc  ranks  between  lead  and  iron;  in  ductility 
between  copper  and  tin.2  In  hardness  it  stands  between  copper  and  tin 
of  the  common  metals,  but  more  exactly  between  silver  and  platinum,  being 
2-5  on  Moh's  scale,3  6  on  Turner's  sclerometer,  and  1,077  on  Bottone's  scale, 
in  which  the  diamond  is  3,010.*  It  is  difficult  to  file. 

Thermal  and  Electrical  Conductivity. — The  thermal  conductivity  of  zinc 
is  variable  (or  has  not  been  determined  accurately)  ranging  from  19 
(Wiedemann)  to  64-1  (Calvert  and  Johnson),  silver  being  100.5  Its  elec- 
trical conductivity  is  16-92  mercury  at  0°  C.  being  unity.  Rating  silver  at 
100,  the  electrical  conductivity  of  zinc  is  24-06  according  to  Becquerell, 
27-39  according  to  Matthiessen,  and  29-90  according  to  Weiller.  The  elec- 
trical resistance  of  a  wire  1  mm.  in  diameter  and  1  m.  in  length  is  0-0724 
ohm,  increasing  with  temperature.  According  to  Roberts- Austen6  the  co- 
efficient of  linear  expansion  of  zinc  is  0-0000291 ;  according  to  Fizeau  it  is 
0-002905  for  100°  from  0°  C.  upward;  according  to  Calvert  and  Johnson  it  is 
0-002193  for  hammered  zinc;  according  to  the  British  Board  of  Trade  units 
it  is  0-002532. 

The  tensile  strength  of  zinc  varies  greatly  according  to  the  mode  of 
preparation,  ranging  from  2,700  Ib.  per  sq.  in.  for  cast  metal  to  17,700  for 
an  annealed  rod.  Roberts- Austen  gives  its  ultimate  tensile  strength  (kind 
of  metal  not  stated)  as  7,000  to  8,000  Ib.  per  sq.  in.7  against  4,600  Ib.  for 
cast  tin  and  19,000  for  cast  copper.  According  to  Wertheim,  a  permanent 
elongation  of  0-5  mm.  per  meter,  of  a  bar  1  mm.  square,  took  place  with 
tensions  of  0-75,  1-00  and  3-20  kg.,  according  as  to  whether  the  bar-  was 
drawn,  annealed  or  cast;  he  found  also  that  the  coefficient  of  rupture  of 
a  wire  1  mm.  in  diameter  was  1-5  kg.  with  cast  metal  and  12-50  with 

a  lawless  fashion,  and,  as  they  cannot  be  12%   Sn,    3-5;    bronze   containing   18%    Sn, 

expected  to  contract  at  the  same  rate  in  all  3-7;  iron  wire,  3-8  to  3-9;  sewing  needles, 

directions,  we  must  be  prepared  for  a  brittle  5  to  5-5. 

ingot"  (Enc.  Brit.,  9th  edition,  XXIV,  786).  *  According  to  Hugueny  the  hardness  of 

1  Gilbert's  Ann.,  XXIV,  104.  zinc  is  0-83  that  of  copper. 

JThe  ductility   of  commercial   zinc  is   in-  8  According   to    Roberts-Austen    the    ther- 

creased  by  subjecting  it  to  regular  and  high  mal  conductivity  of  zinc  is  28-1. 

pressure.  'Introduction    to    the    Study    of    Mctal- 

3  Moh's  scale  of  hardness  for  metals  is  as  lurgy,  revised  edition,  p.  72. 

follows:    lead,  1;  tin,  1-07;  zinc,  2-5;  cop-  7  Op.  cit,  27. 
per,  3-0 ;  gun  metal,  3-3 ;  bronze  containing 


PROPERTIES   OF    ZINC   AND   ITS   ALLOYS.  137 

drawn  and  annealed.  According  to  Karmasch  the  absolute  strength  of  cast 
zinc  is  197-5  kg.  per  sq.  cm.,  and  of  sheet  and  wire  1,315  to  1,560  per 
sq.  cm.  Trautwine  determined  that  a  prism  of  cast  zinc,  1  in.  square  and 
4  in.  high  was  compressed  1/400  of  its  height  by  2,000  lb.,  1/200  by  4,000 
lb.,  1/100  by  6,000  lb.,  1/38  by  10,000  lb.,  and  1/15  by  20,000  lb.,  while 
under  40,000  lb.  it  yielded  rapidly  and  broke  into  pieces. 

CHEMICAL  PROPERTIES. — In  dry  air  zinc  retains  its  luster,  but  in  damp 
it  becomes  covered  with  a  thin,  grayish-white  coat  of  a  basic  carbonate,  which 
protects  it  from  further  oxidation.  This  property  makes  it  valuable  for 
outdoor  uses.  Pettenkoffer  found  that  a  sheet  of  zinc  exposed  as  part  of 
a  roof  at  Munich,  Bavaria,  for  27  years  was  oxidized  only  to  a  depth  of 
0-01  mm.  Zinc  is  electro-positive  to  all  other  common  metals,  except 
magnesium,  and  precipitates  all  the  ductile  metals  from  their  solutions 
with  the  exception  of  magnesium,  iron  and  nickel,  but  is  itself  pre- 
cipitated by  magnesium.  It  dissolves  readily  in  nitric  acid,  but  when  pure 
is  almost  unaffected  by  other  acids,  dilute  or  strong.  Impure  commercial 
zinc,  however,  is  easily  soluble  in  dilute  sulphuric  acid,  and  in  dilute  or 
strong  chlorhydric.  Similarly  pure  zinc  is  unaffected  by  boiling  water,  while 
the  latter  is  decomposed  by  ordinary  metal  with  the  evolution  of  hydrogen, 
zinc  hydrate  being  formed,  but  as  the  metal  becomes  coated  with  an 
envelope  of  the  soluble  hydrate  action  gradually  ceases,  wherefore  even 
impure  zinc  may  be  preserved  indefinitely  in  pure  water.  When  the  zinc 
is  in  a  state  of  extremely  fine  division,  as  in  zinc  gray  (zinc  dust),  water 
is  decomposed  by  it  even  at  ordinary  temperatures.  Sea  water  attacks  zinc 
much  more  rapidly  than  pure  water.  The  difference  in  the  behavior  of 
pure  and  impure  zinc  was  first  pointed  out  by  A.  de  la  Eive  in  1830,  and 
has  been  discussed  by  many  writers,  especially  Pullinger  in  the  Journal  of 
the  Chemical  Society  of  London,  LVII,  815,  and  Werren  in  Berichte  der 
deutschen  Chemischen  Gesellschaft,  XXIV,  1785.  According  to  the  latter, 
pure  zinc  upon  being  put  into  acid  is  immediately  enveloped  by  a  coating 
of.  hydrogen,  which  protects  it ;  upon  boiling  this  coating  is  torn  away  and 
the  zinc  dissolves.  The  solubility  of  zinc  in  sulphuric  acid  is  promoted  by  the 
addition  of  chromic  acid  or  hydrogen  peroxide.  If  a  piece  of  platinum  be 
brought  in  contact  with  the  zinc,  the  latter  dissolves  quickly.  Zinc  dis- 
solves readily  in  cold  nitric  acid,  because  the  latter  oxidizes  the  hydrogen 
evolved. 

Aqueous  solutions  of  the  caustic  alkalies  dissolve  zinc  with  the  evolu- 
tion of  hydrogen,  but  much  more  slowly  than  acids  do.  The  action  is 
more  energetic  when  the  zinc  is  in  contact  with  iron,  forming  a  galvanic 
couple.  Zinc  is  thus  easily  dissolved  in  potash  lye  when  container!  in  an 


138  PRODUCTION   AND   PROPERTIES   OF   ZINC. 

iron  vessel.  The  zinc  shavings  used  for  the  precipitation  of  gold  in  the 
cyanide  process  are  dissolved  quickly  by  the  caustic  alkali  present  in  those 
solutions.  In  the  cyanide  process,  commercial  advantage  is  taken  of  the 
power  of  zinc  to  displace  other  metals,  in  this  case  gold  and  silver,  from 
their  solutions. 

At  red  heat  zinc  is  attacked  by  carbonic  acid  with  the  formation  of  carbon 
monoxide  and  zinc  oxide.  Sulphur  also  unites  with  it  at  red  heat,  forming 
zinc  sulphide,  but  the  combination  is  incomplete,  even  when  both  the  zinc 
and  the  sulphur  are  finely  divided  and  intimately  mixed,  because  the 
particles  of  zinc  are  protected  from  further  action  by  the  infusible  envelope 
of  zinc  sulphide  which  is  first  formed.  By  rapid  heating  with  sulphide  of 
mercury,  as  well  as  sulphide  of  calcium,  zinc  is  completely  changed  to 
sulphide.1  In  smelting  zinc  with  oxide  of  lead  the  latter  is  reduced  to  metal 
and  zinc  oxide  is  formed.  In  smelting  with  carbonates  of  the  alkalies  zinc 
oxide  is  also  formed,  carbonic  dioxide  being  disengaged,  but  with  sulphates 
of  the  alkalies  a  mixture  of  zinc  oxide  and  zinc  sulphate  is  formed,  and  sul- 
phurous anhydride  is  set  free. 

IMPURITIES  OCCURRING  IN  ZINC  AND  THEIR  EFFECT. — The  impurities 
which  occur  in  commercial  zinc,  often  amounting  to  as  much  as  2%  of  the 
latter,  are  lead,  iron,  cadmium,  copper,  carbon,  silicon,  arsenic,  antimony, 
sulphur,  tin,  silver,  thallium,  indium  and  gallium.  The  most  common  of 
these  are  lead,  iron  and  cadmium,  while  the  five  elements  last  mentioned 
are  rare.  Silver  has  been  detected  in  zinc  from  Brixlegg  in  Tyrol,  and  tin 
in  New  Jersey  metal.2  Freiberg  zinc  has  contained  0-0393  to  0-0524% 
indium.  Thallium  is  present  in  many  specimens  of  blende  and  calamine 
from  Theux  and  Nouvelle  Montagne,  Belgium,  and  appears  in  the  metal 
distilled  from  them.  It  has  also  been  detected  in  the  mother  liquors  of  the 
zinc  sulphate  works  near  Goslar  in  the  Lower  Harz. 

Lead. — Lead  is  found  in  most  makes  of  spelter,  being  invariably  distilled 
to  a  considerable  extent  along  with  the  zinc  when  it  occurs  in  the  ore.3  An 
excess  of  lead  can  be  separated,  however,  since  the  capacity  of  zinc  for  hold- 
ing it  is  limited,  varying  with  the  temperature;  it  is  the  greater,  the  higher 

1  Schnabel,  Handbuch  der  Metallhiitten-  lead,  while  under  other  conditions  an  ore 

kunde,  II,  5.  comparatively  high  In  lead  may  afford  a 

7Kolbech  has  isolated  crystals  of  cassi-  really  good  grade  of  spelter.  At  a  certain 

terite  in  the  blende  from  Freiberg.  works  in  Europe  an  ore  assaying  14%  Pb 

3  The  extent  to  which  lead  is  distilled  over  yields  a  spelter  with  only  1%  Pb,  while 

with  the  zinc  depends  upon  the  percentage  Picard  and  Sulman  claim  to  obtain  a  spelter 

existing  in  the  ore  and  the  temperature  containing  only  0-5%  Pb  by  distillation  of 

and  other  conditions  under  which  the  ope-  ore  assaying  24%  Pb.  On  the  other  hand, 

ration  is  managed.  Under  certain  condi-  the  ore  distilled  in  Upper  Silesia,  which  is 

tions  an  ore  not  very  high  in  lead  may  very  much  lower  in  lead,  yields  a  spelter 

yield  a  spelter  containing  a  good  deal  of  holding  2  or  3%  Pb. 


PROPERTIES   OF   ZINC   AND   ITS   ALLOYS.  139 

the  temperature.  According  to  Roessler  and  Edelmann,  zinc  will  hold 
1-7%  Pb  at  its  melting  temperature  and  5-6%  at  650°  C.1  Any  excess  of 
lead  beyond  those  proportions  will  sink  unalloyed  to  the  bottom  of  the 
pot.  A  moderate  tenor  in  lead  makes  zinc  malleable  and  ductile,  and  con- 
sequently is  desirable  in  metal  which  is  to  be  rolled,  but  with  an  increasing 
proportion  it  becomes  tender.  Consequently  the  percentage  of  lead  in  zinc 
intended  for  rolling  must  be  limited,  else  the  sheets  will  tear  and  crack 
under  the  rolls.  A  tenor  of  1-5%  Pb  will  permit  the  rolling  of  the  zinc 
without  cracking  the  sheets,  but  will  unfit  them  for  some  purposes.  The 
weakness  and  softness  of  the  sheets  increase  as  the  percentage  of  lead 
increases.  Zinc  with  3%  Pb  may  still  be  rolled,  but  it  is  very  weak.  The 
presence  of  a  considerable  quantity  of  lead  unfits  zinc  for  sheet  for  graphical 
purposes,  which  requires  smooth,  glossy  surfaces  such  as  are  afforded  by  a 
good  grade  of  zinc,  while  metal  containing  much  lead  gives  a  gray,  rough 
surface;2  lead  is  also  objectionable  in  zinc  for  making  the  better  grades  of 
brass,  but  a  moderate  percentage  does  not  unfit  it  for  use  in  making  inferior 
grades. 

Iron. — Iron  may  be  present  in  zinc  to  the  extent  of  several  per  cent,  but 
the  tenor  seldom  exceeds  0-2%.  Up  to  that  figure,  according  to  Karsten,  the 
presence  of  iron  does  not  affect  importantly  the  properties  of  zinc,  but  the 
general  tendency  of  the  impurity  is  to  make  the  metal  less  fluid,  less 
malleable,  less  strong,  and  harder  and  more  brittle.3  Spelter  may  contain 
0-125%  Fe  and  still  be  a  good  metal  for  rolling  to  sheet,  but  with  more  than 
that  percentage  its  bad  effects  become  apparent,  and  between  0-20  and  0-25% 
become  very  marked  and  interfere  very  seriously  with  the  rolling  of  the 
metal.  Commonly  the  percentage  of  iron  in  commercial  zinc  is  between 
0-01  and  0-05%,  but  according  to  Jensch  (in  Zts.  f.  angew.  Chem.,  1890, 
p.  13)  spelter  produced  from  the  dust  collected  from  Upper  Silesian  iron 
furnaces,  containing  17  to  22%  Zn  and  23  to  25-5%  FeO,  has  a  tenor  of 
0-71%  Fe.  That  zinc  can  hold  a  still  greater  percentage  of  iron  is  shown  by 
the  hard  product  obtained  in  the  refining  of  crude  zinc,  which  segregates 

1  In     ordinary     commercial     refining     by  shows   as  bluish  flecks.     The  microscopical 
gravity  separation  of  the  lead  from   crude  appearances  of  pure  zinc  and  zinc  contamt- 
molten  spelter,  the  lead  content  of  the  lat-  nated  with  lead  are  described  by  H.  Behrena 
ter  is  reduced  to  about  1%.     According  to  in  Das  mikroscopische   Gefiige  der  Metalle 
Spring  and   Romanoff  zinc  will   hold  25-5%  und     Legirungen,     published     by     L.     Voss, 
Pb  at  900°  C.,  7%  at  650°,  and  will  still  re-  Hamburg  and  Leipsic,  1894,  p.  56. 

tain  1-5%  at  419°.  3  The   American    brass   trade   has   become 

2  To  ascertain  whether  zinc  is  suitable  for  very   particular  as   to  the   iron   content   of 
graphical    purposes,    Augurer    recommends  spelter   and   now   imposes  a   limit   of  about 
brightening   a    small     spot    with    a    finely  0-05%   Fe   as   the  maximum   permissible  ia 
ground  scraper  and  examining  the  fresh  sur-  Western  metal  to  be  used  for  brass  manu- 
face  with  a  microscope.     The  zinc  appears  facture. 

as    ashy,    star-like   scales,    while    the    lead 


140  PRODUCTION   AND   PROPERTIES   OF   ZINC. 

between  the  lead  and  zinc,  while  in  galvanizing  iron  an  alloy  of  zinc  with 
4%  Fe  separates  in  the  kettles.  Herapath  found  7%  Fe  in  zinc  taken 
directly  from  the  condensers  of  a  distilling  furnace. 

Cadmium. — Cadmium  seldom  occurs  in  zinc  except  in  insignificant  quan- 
tities, which  have  no  injurious  influence ;  if  the  ore  contains  a  comparatively 
high  percentage  of  cadmium,  the  proportion  in  the  spelter  will  still  be  low, 
since  cadmium  is  a  more  volatile  metal  than  zinc  and  for  the  more  part 
fails  to  be  condensed.  If  present  in  larger  quantity  than  ordinarily  the 
tendency  is  to  make  the  spelter  more  brittle,  giving  it  a  fine-grained  fracture, 
but  it  is  said  that  zinc  with  15%  Cd  may  still  be  rolled.  If  the  spelter  is 
to  be  used  for  the  manufacture  of  zinc  white,  the  presence  of  cadmium  is 
objectionable,  since  either  cadmium  oxide  or  sulphide  may  give  the  product 
41  yellowish  tinge. 

Copper  and  Tin. — Copper  makes  zinc  harder  and  more  brittle,  even  if 
only  0-5%  be  present,  so  that  in  rolling  it  cracks  at  the  edge  and  the  sheets 
cannot  be  folded  without  breaking.  Tin  also  makes  it  harder  and  more 
brittle.  According  to  Karsten,  zinc  containing  \%  Sn  is  rendered  so 
brittle,  at  a  temperature  at  which  it  would  otherwise  be  pliant,  that  when 
rolled  it  cracks  at  the  edges  of  the  sheets.  Both  copper  and  tin  are  of  rare 
occurrence  in  spelter.  Missouri  brands  have  shown  0-0013  to  0-1123%  Cu; 
Lehigh  Zinc  Co.,  Penn..  0-530%  Cu  (an  old  analysis) ;  Eeckehiitte  and 
Georgshtitte,  Upper  Silesia,  0-0002%  Cu;  Freiberg,  Saxony,  0-07%  Sn; 
while  tin  has  also  been  noted  in  New  Jersey  and  Welsh  spelter.  Zinc  re- 
melted  from  roofing  scrap  may  contain  more  tin,  due  to  the  solder.1 

Rare  Metals. — Of  the  uncommon  metallic  impurities  the  following 
maxima  have  been  noted:  Silver,  0-0017%  in  spelter  from  Upper  Silesia; 
thallium,  140%  in  a  specimen  smelted  from  scrap;2  indium,  0-0524%  in 
spelter  from  Freiberg.  Saxony;  magnesium,  0-46%;  aluminum,  0-17%; 
antimony,  0-0249%  in  zinc  from  Missouri.  Traces  of  manganese  and 
bismuth  have  been  reported. 

Arsenic  and  Antimony. — Arsenic  if  present  in  large  quantity  makes  the 
spelter  brittle  and  difficult  to  melt.  Arsenic  combines  with  zinc  in  various 
proportions,  forming  alloys,  at  moderate  temperatures.  The  presence  of  as 
much  as  0-0603%  has  been  noted  in  Missouri  zinc.  Any  arsenic  at  all  unfits 
zinc  for  the  development  of  hydrogen  where  arseniureted  gas  would  be  objec- 
tionable.  Zinc  which  is  to  be  used  for  precipitating  gold  from  cyanide 
solution  should  bo  free  from  arsenic,  because  of  the  danger  in  treating  tho 

1  Polir.  Berg-  u.Htittenm.  Ztg.,1888.  p.  28.        1-40%  thallium,  7-19%  As,  2%  Fe  and  some 
1  This  was  a  very  remarkable  crude  zinc       ZnO. 
reported  by  Kosmann  in  Chem.   Ztg.,   1886,        No.  HO.     It  contained  7-15%  Pb,  0-09%  Cd, 


PROPEUTIES   OF   ZINC   AND   ITS   ALLOYS.  141 


precipitate  with  acid,  fatalities  having  occurred  in  the  United  States  from 
arseniureted  hydrogen  developed  from  impure  zinc  in  that  manner.  The 
effect  of  antimony  on  zinc  is  said  to  be  similar  to  that  of  arsenic,  but  prob- 
ably has  not  been  much  studied. 

Sulphur  and  Carbon-. — Sulphur  occurs  in  numerous  spelters  up  to 
0-0741%.  Its  effect  has  not  been  studied,  but  so  far  as  known  it  does  not 
seem  to  be  deleterious.1  According  to  Funk,  the  sulphur  contained  in 
spelter  is  not  chemically  combined,  but  exists  as  ZnS  carried  over  from  the 
charge  in  distillation.2  Funk  states  also  that  the  carbon,  which  has  been 
found  in  certain  zinc  to  the  amount  of  0-1775%,  is  mechanically  carried 
over,  and  not  chemically  combined;  and  considers  the  odor  of  the  gases 
generated  by  action  of  acids  on  zinc  to  be  due  principally  to  hydrogen 
sulphide  and  not  to  hydrocarbons.  Eodwell  showed  that  the  black  flocks 
which  remained  after  dissolving  commercial  zinc  in  acid  consisted  of  carbon, 
lead  sulphate  and  a  trace  of  iron.3  The  influence  of  carbon  on  zinc  has 
not  been  studied,  but  as  in  the  case  of  sulphur,  so  far  as  known  it  is  neither 
harmful  nor  advantageous. 

Chlorine  to  the  amount  of  0-2  to  0-3%  was  found  by  Kunzel  in  spelter 
made  from  the  crusts  from  a  Belgian  works.4  Although  this  metal  con- 
tained lead  and  iron  only  in  traces  and  to  the  eye  was  of  good  quality, 
it  could  not  be  rolled.  Jensch  has  also  called  attention  to  the  presence  of 
chlorine  in  zinc.  Silicon  has  been  found  in  Missouri  zinc  up  to  0-1374%. 

Oxygen  occurs  frequently  in  zinc  in  the  form  of  zinc  oxide,  which  may 
commingle  with  the  metal  collected  in  the  condensers  or  in  the  subsequent 
handling.  When  present  in  considerable  quantity  it  produces  a  pasty  metal 
(burned  zinc)  which  gives  castings  without  sharp  edges,  brittle,  and 
difficult  to  work  with  chisel  and  file.  Such  burned  zinc  is  apt  to  be  produced 
by  any  imperfection  in  the  distillation  process  which  causes  the  zinc  vapor 
to  be  oxidized;  such  as  a  deficiency  of  carbon  in  the  charge  and  carrying  the 
distillation  too  far,  whereby  the  atmosphere  of  carbonic  monoxide  in  the 
retort  is  expelled  by  furnace  gases  penetrating  the  walls  and  the  remaining 
zinc  vapor  is  oxidized,  the  oxide  going  over  into  the  condenser.5 

ZINC  ALLOYS. — Zinc  forms  alloys  with  most  of  the  common  metals  at  tem- 
peratures sufficiently  high  to  insure  fusion.  These  alloys  are  usually  white, 

1  It  is  considered  by  some,  however,  that  sulphur  and  iron  may  be  largely  prevented, 

even  a  small  amount  of  sulphur  may  serl-  Zinc  will   be  contaminated  with  iron  from 

ously  affect  the  ductility  of  the  spelter,  in-  the  tools  and  molds  even  when  It  is  quite 

asmuch    as    the    sulphur    unites    with    iron  free  from  sulphur. 

when  the   hot  zinc   comes  in   contact  with  *  Zts.  f.  anorgan.  Chem.,  1896,  p.  49. 

that  metal  and  thereby  the  zinc  is  rendered  'Chemical  News,  January,  1861,  No.  57. 

cold    short.     By    coating    the    molds    with  *Berg-u.  Hiittenm.  Ztg.,  1874,  p.  6. 

beeswax  and  chalk  the  reaction  between  the  •  Kerl.  The  Mineral  Industry,  V,  613. 


142  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

crystalline,  brittle  compounds,  and  are  of  little  importance  with  the  excep- 
tion of  the  copper-zinc  series  and  the  newly  investigated  aluminum-zinc 
series. 

Aluminum  and  Zinc. — An  alloy  of  zinc  and  aluminum  which  possesses 
interesting  and  valuable  properties  has  been  described  by  Professor  Durand, 
of  Cornell  University.  It  consists  of  two-thirds  aluminum  and  one-third 
zinc.  This  alloy  is  said  to  be  the  equal  of  good  cast  iron  in  strength  and 
superior  to  it  in  elastic  limit.  Its  color  is  white.  It  takes  a  fine,  smooth 
finish  and  does  not  readily  oxidize.  It  melts  at  a  dull  red  heat  or  slightly 
below,  probably  at  about  800°  to  900°  F.,  and  is  very  fluid,  running  freely 
to  the  extremities  of  the  mold  and  filling  perfectly  small  or  thin  parts ;  in 
that  respect  it  is  said  to  be  superior  to  brass,  but  it  is  brittle  and  hence 
unsuited  to  pieces  which  require  the  toughness  possessed  by  brass.  The 
tensile  strength  of  the  alloy  was  found  to  be  approximately  22,000  lb.  per 
eq.  in.,  and  its  specific  gravity  3-3.1 

Doctor  Joseph  W.  Richards  confirms  the  general  correctness  of  Professor 
Durand's  statements  and  adds  that  experience  in  making  the  alloy  has  led 
to  considerable  improvements  in  the  results  obtained.2  There  is  now  no 
difficulty  in  producing  castings  of  the  alloy  showing  a  tensile  strength  of 
40,000  lb.  This  alloy  resembles  closely  in  its  characteristics  a  high-carbon 
steel,  being  extremely  rigid,  slightly  elastic  and  breaking  short  with  a  fine- 
grained fracture.  It  works  well  under  tools,  in  turning  or  boring,  not  re- 
quiring lubrication.  It  is  the  hardest  and  strongest  of  the  available  alloys  of 
zinc  and  aluminum,  takes  a  high  polish  and  retains  its  color  well,  but  it  is 
not  so  resistant  to  shock  as  are  the  other  alloys  containing  less  zinc.  Doctor 
Eichards  reports  the  specific  gravity  of  this  alloy  as  3-8  and  states  that  a 
contraction  of  17%  takes  place  during  the  alloying  of  its  ingredients,  which 
observation  'suggests  the  cause  of  its  great  strength. 

Although  there  will  be  numerous  uses  for  the  strong,  rigid  alloy  above 
described,  Doctor  Eichards  considers  that  the  alloy  consisting  of  three  parts 
of  aluminum  and  one  part  of  zinc  will  be  the  most  valuable  of  the  zinc- 
aluminum  series.  The  latter  alloy,  containing  25%  Zn,  is  softer  than  the 
other  one,  which  contains  33%%  Zn.  Its  elastic  limit  is  about  the  same, 
with  a  slight  elongation  before  breaking;  its  tensile  strength  is  35,000  lb. 
per  sq.  in.  It  is  not  malleable,  but  on  the  other  hand  it  is  not  brittle 
inasmuch  as  it  bends  slightly  before  breaking.  The  latter  property  is  a 
valuable  one,  since  it  enables  a  casting  to  be  straightened  to  a  certain  extent 
by  hammering.  Eemarkably  clean  and  sharp  castings  can  be  made,  when 

1  The  Mineral  Industry,  VI,  29. 

8  Eng.    &   Min.    Journ.,   Nov.    30,    1901,   p.  715. 


PROPERTIES    OF    ZINC    AND    ITS    ALLOYS.  143 


experience  has  been  attained  as  to  the  proper  gating  of  the  mold  and  the 
exact  temperature  of  casting.  In  the  case  of  both  of  these  alloys  overheating 
in  the  crucible  must  be  avoided;  also  the  use  of  iron  stirring  implements, 
because  oxide  and  dross  do  not  separate  easily  out  of  the  metals  and  may  be 
poured  into  the  mold  causing  injury  to  the  casting.  The  specific  gravity  of 
the  alloy  containing  25%  Zn  is  3*4.  A  contraction  of  14%  takes  place 
during  the  alloying. 

The  alloy  of  75%  Al  and  25%  Zn,  when  properly  made  from  pure  metals, 
is  equal  to  the  best  brass  in  the  lathe,  under  the  drill,  and  in  not  clogging  the 
file.  It  casts  soundly,  takes  a  high  polish  and  has  as  fine  a  color  as  the 
best  aluminum.  It  is  not  so  hard  and  short  as  the  alloy  containing 
331/3%  Zn,  nor  is  it  quite  so  strong,  but  it  has  supplanted  the  latter  for 
most  purposes  because  of  its  better  working  qualities  and  greater  reliability 
under  shock.  It  is  now  used  for  the  manufacture  of  scale  beams,  surveying 
and  astronomical  instruments,  and  light  machine  parts.  Its  use  is  increas- 
ing rapidly. 

Below  25%  Zn,  the  strength  and  hardness  of  the  zinc-aluminum  alloys 
decrease  rapidly.  The  alloy  with  15%  Zn  has  in  castings  an  elastic  limit 
of  16,000  Ib.  per  sq.  in.,  a  tensile  strength  of  22,330  Ib.  and  an  elongation  of 
6%  in  two  inches.  It  can  be  rolled  and  drawn  into  wire  if  frequently  an- 
nealed. All  of  the  alloys  of  zinc  and  aluminum  with  less  than  15%  Zn  can 
be  forged,  rolled  or  drawn.  They  gradually  become  softer  and  weaker  and 
require  lubrication  of  the  tools  during  working. 

The  alloys  of  zinc  and  aluminum  which  are  high  in  zinc  appear  to  be 
destitute  of  specially  valuable  mechanical  properties.  Even  the  alloy  con- 
sisting of  50%  Al  and  50%  Zn,  which  has  a  specific  gravity  of  4,  falls  under 
that  category.1 

Antimony  and  Zinc.— With  antimony  zinc  unites  readily  in  all  propor- 
tions, forming  alloys  which  are  brittle  and  fusible,  and  exhibit  a  close- 
grained,  dark-gray  fracture  when  much  antimony  is  present.  An  alloy  con- 
sisting of  equal  parts  antimony  and  zinc  is  of  a  bright,  sky-blue  color,  and 
has  the  peculiar  property  of  writing  upon  glass.  Even  a  small  proportion 
of  antimony  renders  zinc  bluish,  and  the  presence  of  more  than  0-5%  may 
be  detected  in  that  manner.  Zinc-antimony  alloys  have  found  a  limited 
application  in  thermopiles. 

Bismuth  and  Zinc. — Zinc  unites  with  bismuth  when  both  are  melted,  but 
upon  cooling  two  distinct  layers  are  formed,  the  upper  containing  2-4%  Bi 

1  The  above  notes  as  to  the  properties  of  the  zinc-aluminum  alloys  are  abstracted 
from  the  paper  by  Doctor  Richards  previously  referred  to. 


144  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

and  97-6%  Zn,  and  the  lower  85-7  to  914%  Bi  and  14-3  to  8-6%  Zn.     In 
this  respect  bismuth  behaves  with  zinc  very  much  as  lead  does. 

Copper  and  Zinc. — Zinc  and  copper  unite  in  all  proportions.,  forming 
alloys,  which  under  the  name  of  brass,  are  of  widespread  industrial 
application.  These  compounds  vary  much  in  their  properties  according  to 
their  composition.  Those  containing  upward  of  80%  Cu  are  reddish-yellow 
to  red;  with  less  than  48%  Cu  they  are  gray  to  white;  in  the  intermediate 
stages  they  are  shades  of  yellow.  The  hardness  of  these  alloys  is  usually 
greater  and  the  melting  point  lower  than  those  calculated  as  the  mean  of 
their  constituents.  The  alloys  with  more  than  62%  Cu  can  only  be  rolled 
cold;  those  with  about  60%  Cu  can  be  rolled  hot  or  cold,  but  are  less  ductile 
and  tough  than  the  higher  grade ;  those  with  about  50%  Cu  cannot  be  rolled, 
either  hot  or  cold;  with  less  than  50%  Cu  they  lose  their  yellow  color  and 
become  brittle,  while  their  fusibility  increases.  The  chief  application  of  the 
alloy  containing  about  50%  Cu  is  for  solder  for  copper  and  brass. 

Since  the  ductility  of  the  copper-zine  alloys  increases  with  the  percentage 
of  copper,  the  best  kinds,  such  as  red  brass,  gilding  metal,  and  percussion 
cap  metal  are  made  to  contain  80  to  96%  Cu.  Dutch  metal  contains  80  to 
85%  Cu;  Prince's  metal,  75%  Cu;  best  English  sheet  brass,  70  to  72%  Cu; 
ordinary,  66-67%  Cu;  common,  63%  Cu,  and  yellow  metal,  60%  Cu.  The 
last,  though  somewhat  deficient  in  ductility  and  toughness,  possesses  the 
great  advantage  that  it  can  be  rolled  either  hot  or  cold. 

Brass  is  made  by  melting  together  copper  and  zinc  in  the  proper  pro- 
portion. Laurie  has  shown1  that  there  is  only  one  definite  alloy  of  copper 
and  zinc,  it  corresponding  approximately  to  the  formula  CuZn2,  containing 
about  33%  Cu  and  67%  Zn,  and  that  all  other  copper-zinc  alloys  may  be 
considered  as  solidified  solutions  of  this  definite  alloy  in  an  excess  of  one 
of  its  constituents.  The  definite  alloy  itself  is  hard  and  brittle,  and  of 
little  or  no  practical  value. 

Gold  and  Zinc. — With  gold,  zinc  forms  a  series  of  alloys  which  are  pale 
yellow  when  the  gold  is  in  excess,  and  become  greenish  as  the  proportion  of 
zinc  increases.  For  jewelry  part  of  the  copper  is  often  replaced  by  brass, 
the  zinc  in  the  latter  giving  the  gold  a  more  desirable  color,  but  the  presence 
of  much  zinc  makes  the  alloy  hard  and  difficult  to  work. 

Iron  and  Zinc. — With  iron  zinc  forms  a  series  of  alloys  which  are  gen- 
erally hard,  white  and  brittle.  A  fine-grained  alloy  containing  about 
95%  Zn  and  5%  Fe,  which  is  darker  in  color  than  pure  zinc,  is  produced 
in  the  process  of  galvanizing.  This  is  known  as  "hardhead"  and  "hard 
zinc."  Alloys  richer  in  iron  are  obtained  by  liquating  hard  zinc  and  fusing 

1  Journal  of  the  Chemical  Society  of  London,  LIU,  106,  and  LV,  677. 


PROPHTmKS    OF    ZINC    AND    ITS    ALLOYS.  U5 

the  friable  residue;  alloys  with  as  much  as  30%  Fe  being  produced  in 
that  manner.  They  are  also  prepared  by  immersing  clean  iron  wire  or  sheet 
in  zinc  heated  to  near  its  boiling  point.  These  alloys  find  industrial  applica- 
tion in  the  manufacture  of  "delta  metal"  and  similar  compounds,  which  are 
brasses  with  the  addition  of  from  0-25  to  4%  Fe.  The  iron  imparts  hard- 
ness, toughness  and  tenacity,  and  the  alloy  can  be  rolled  hot  or  cold. 

Lead  and  Zinc. — With  lead,  zinc  behaves  in  much  the  same  manner  as 
with  bismuth,  uniting  readily  when  both  are  molten,  but  separating  into 
two  layers  upon  cooling.  The  upper  consists  chiefly  of  zinc  with  about 
1'5%  Pb,  and  the  lower  is  lead  with  1-2%  Zn.  Ordinary  commercial  zinc  is 
an  alloy  containing  about  \%  Pb,  which  enables  the  zinc  to  receive  a  good 
polish,  and  increases  its  malleability.  The  presence  of  that  amount  of 
lead,  therefore,  is  desirable  in  zinc  for  rolling  into  sheets,  but  an  excess  of 
lead  is  undesirable.  Lead  is  also  undesirable  in  zinc  which  is  to  be  used  for 
the  manufacture  of  brass,  especially  the  superior  grades. 

Mercury  and  Zinc. — With  mercury  zinc  readily  unites,  forming  a  series  of 
white  brittle  amalgams  which  become  pasty  when  mercury  is  in  excess.  Zinc 
amalgams  are  easily  obtained  by  adding  zinc  to  mercury  heated  nearly  to  its 
boiling  point.  Zinc  plates  for  galvanic  batteries  are  coated  with  mercury  by 
first  cleaning  the  surface  of  the  zinc  with  dilute  sulphuric  acid  and  then 
rubbing  the  mercury  over  the  clean  surface.  An  amalgam  of  zinc  and  tin 
is  used  on  the  rubbers  of  frictional  electric  machines.1 

Silver  and  Zinc. — Zinc  unites  with  silver  at  high  temperatures,  forming 
a  series  of  white  alloys.  Those  with  5,  10  or  20%  Zn  are  ductile  and  can 
be  rolled  like  silver.  They  are  more  fusible  than  the  corresponding  copper- 
silver  alloys.  At  low  temperatures  zinc  and  silver  do  not  unite  readily. 

Tin  and  Zinc. — With  tin,  zinc  readily  unites  in  all  proportions,  the  result- 
ing alloys  being  generally  harder  than  tin  but  softer  than  zinc.  Their  color 
is  in  all  cases  white,  and  their  fracture  crystalline,  though  their  appearance 
varies  with  the  mode  of  preparation.  The  alloys  of  tin  and  zinc  are  not 
uniform  in  composition,  since  the  tin  tends  to  separate  and  collect  at  the 
bottom  on  cooling.  Tin-zinc  alloys  are  used  to  a  slight  extent  for  castings 
for  ornamental  purposes.  A  detailed  description  of  these  alloys,  based  on 
the  work  of  Guettier  and  Rudberg,  is  given  in  Hiorns'  Mixed  Metals,  pp.  249 
to  253. 

An  addition  of  tin  to  a  mixture  of  zinc  and  lead  causes  those  metals  to 
alloy  to  an  extent  to  which  they  will  not  by  themselves.  If  tin,  lead  and 
zinc  are  melted  together  and  left  at  rest  in  a  fused  condition  no  separation 

1  Thorpe,   Dictionary   of  Applied   Chemistry ;  as  to  the  literature  of  zinc  amalgams 
vide  .Tourn.  Soc.  Chem.  Ind.,  IX,  p.  512. 


146 


PRODUCTION    AND   PROPERTIES    OF   ZINC. 


takes  place  if  the  proportion  of  tin  exceeds  a  certain  amount;  but  if  the 
quantity  of  tin  be  less  than  that,  the  mixture  separates  into  two  layers,  each 
layer  consisting  of  a  ternary  alloy  of  the  three  metals. 

Other  Binary  Alloys. — Zinc  alloys  with  magnesium,  nickel,  cobalt, 
tellurium  and  sodium.  According  to  Vautin1  the  zinc  used  for  precipitat- 
ing gold  from  cyanide  solutions  may  be  advantageously  alloyed  with  \%  of 
sodium. 

Complex  Alloys. — Besides  the  binary  alloys,  zinc  enters  into  the  com- 
position of  a  considerable  number  of  alloys  containing  three  or  more  metals, 
which  are  more  or  less  useful  in  the  arts.  The  following  are  the  most 
important  of  these : 


Cu. 

Zn. 

Sn. 

Pb. 

Ni. 

Sb. 

Fe. 

Brass  •  ••  .  .  o 

(63-00 

34-00 

"      .                6 

1  7  2  '  00 
70-29 

27  '00 
29-26 

0-17 

0'28 

Muntz's  Metal  c 

(60-00 

40-00 

Stereo's  Metal  d 

55-33 

41-80 

4  "66 

Aich's  Metal    e 

60-00 

38-12 

1'50 

Mosaic  Gold  

65-00 

35-00 

Pinchbeck 

83-33 

16  '76 

180-00 

20-00 

Bronze  ...                     / 

j  88  '  00 
95-00 

12  "00 

i-oo 

4-00 

"         g 

(82-70 

1-80 

4'70 

h 

j  71'4Q 
74-00 

6*00 

10-00 

I'OO 

5  "90 
IS'OO 

(80-00 

7-00 

13-00 

"         t 

190-00 

7-00 

3-00 

Delta  Metal  

55-10 

43-47 

0'37 

1'08 

Silicon  Bronze  ...        .             m 

97-12 

1'12 

1'14 

43'80 

40'60 

15*60 

English  German  Silver  

61-30 

19-10 

19-10 

Sheffield       "             " 

57  '00 

19-00 

24'00 

Berlin  Argentan.  .. 

52-00 

22-00 

26  00 

"*****"* 

Ashberry  "Metal 

2  '80 

77  '80 

19  '40 

Anti-Friction  Metal.  . 

5'00 

85-00 

10  '00 

Babbitt's  Metal  

4-00 

69-00 

19-00 

5'00 

3'00 

Tombac  (English)  

86-38 

13-61 

"          (Viennese). 

97'80 

2'20 

Watchmakers'  Alloy  o 

58-86 

40-22 

1'90 

a  Typical  brass,  b  Wire;  always  brittle  if  lead  reaches  2%;  tin  may  vary  from  0-1  to 
0-5%.  c  Used  for  sheathing  ships,  d  An  Austrian  metal  used  for  ordnance,  e  This  and 
Sterro's  metal  are  remarkable  for  their  great  strength,  viz.,  85,080  Ib.  per  sq.  in. ;  another 
analysis  of  Aich's  metal  is  Cu  60-20%,  Zn  38-10%,  Fe  1-60%,  total  99-90%.  f  British  bronze 
coinage,  g  Japanese  art  bronze,  h  Chinese  art  bronze,  i  Used  for  bearings  for  heavy 
axles,  m  Used  for  telephone  wire,  n  A  Chinese  alloy,  o  A  gold-like  alloy  used  by  watch- 
makers. 


Part  of  the  tin  in  gun  metal  and  in  bearing  metal  is  frequently  replaced 
by  zinc,  the  density  and  wearing  properties  of  those  alloys  being  thereby 
increased.  For  the  same  reason  the  bronze  coinage  of  Great  Britain  contains 

1  Journ.  Soc.  Chem.  Ind.,  1891,  p.  96. 


PROPERTIES    OF    ZINC    AND    ITS    ALLOYS.  147 


\%  Zn.  Zinc  is  also  present  in  some  varities  of  aluminum  bronze, 
manganese  bronze  and  other  similar  alloys.  The  "Biddery  ware,"  manu- 
factured in  India,  usually  contains  about  90%  Zn  with  copper,  lead  and 
tin  in  different  proportions. 

Zinc,  copper  and  nickel  form  a  nickel  bronze  of  great  strength,  and  alloys 
of  that  nature  have  been  proposed  for  making  high-pressure  steam  fittings. 
They  are  little  subject  to  corrosion  and  in  some  respects  are  considered 
preferable  to  steel  castings.  According  to  Sergius  Kern  (Chemical  News, 
1900)  the  alloy  composed  of  70%  Cu,  12-5%  Zn  and  17-5%  M  has  a 
tensile  strength  of  26  tons  per  sq.  in.,  and  an  elongation  of  23%  in  two 
inches,  while  the  alloy  with  70%  Cu,  10%  Zn  and  20%  Ni  has  a  strength 
of  36  tons  and  elongation  of  14  to  17%. 

Wilder's  metal  coating  is  an  alloy  consisting  of  84%  Zn,  14%  Sn, 
1-5%  Pb  and  0-5%  Al,  which  is  intended  to  take  the  place  of  ordinary 
spelter  in  galvanizing.  The  tin  reduces  the  melting  point  of  the  alloy 
below  that  of  pure  spelter.  The  function  of  the  lead  is  to  give  more  fluidity 
to  the  alloy.  The  aluminum  is  claimed  to  improve  the  appearance  of  the 
coating. 

A  manganese  bronze  composed  of  53%  Cu,  42%  Zn,  3-75%  Mn  and 
1-25%  Al,  is  said  to  make  a  very  strong  and  tough  -alloy,  suitable  for  pro- 
peller wheels,  gears,  etc.,  and  for  mining  screens,  being  not  attacked  by  acid 
mine  waters. 

The  property  of  zinc  to  form  alloys  with  gold  and  silver  has  already 
been  referred  to.  Mention  has  been  made,  also,  in  a  previous  chapter,  of 
its  power  to  rob  molten  lead  of  those  metals  when  alloyed  therewith,  and 
the  application  of  that  property  in  the  desilverization  of  lead  bullion.  At 
the  same  time  the  zinc  completes  the  refining  of  the  lead  by  alloying  with, 
and  thus  removing,  the  last  traces  of  copper,  tellurium  and  other  im- 
purities. 

Zinc  can  be  separated  from  alloys  of  which  it  is  a  constituent  by  heating 
to  a  temperature  above  its  boiling  point.  This  process  is  applied  techni- 
cally on  a  large  scale  in  the  refining  of  desilverized  lead.  After  the 
gold  and  silver  have  been  removed  from  the  softened  lead  by  the  addition 
of  zinc  and  skimming  off  the  crusts,  the  lead  remains  saturated  with  zinc, 
the  percentage  varying  according  to  the  temperature  but  ranging  usually 
from  0-6  to  1%.  In  order  to  produce  commercial  lead  the  product  of  the 
desilverizing  kettles  is  run  into  a  reverberatory  furnace  wherein  the  zinc 
is  burned  off. 


VII 
CHEMISTRY  OF  THE  COMPOUNDS  OF  ZINC. 

The  chemical  combinations  of  zinc  which  play  an  important  part  in 
ordinary  method  of  recovering  the  metal  are  especially  the  sulphide,  the 
sulphates  (neutral  and  basic),  the  oxide,  the  carbonates  and  the  silicates. 
In  the  methods  which  have  come  into  use,  however,  for  the  treatment  of 
zinky  mixed  ores  and  the  numerous  processes  which  have  been  proposed  for 
that  purpose,  many  of  the  other  combinations  of  zinc  are  produced,  and  in 
view  of  the  great  interest  in  the  development  of  such  processes  it  is  useful 
to  summarize  rather  fully  the  properties  of  the  chemical  compounds  of 
the  metal,  especially  the  more  important  of  them. 

SULPHIDE. — Zinc  sulphide  (ZnS)  occurs  in  nature  as  the  mineral  blende. 
It  may  be  produced  artificially  by  (1)  heating  zinc  oxide  with  sulphur;  (2) 
heating  zinc  oxide  in  a  stream  of  hydrogen  sulphide;  (3)  heating  zinc 
shavings  with  mercury  sulphide;  (4)  heating  finely  divided  zinc  with 
alkaline  polysulphides ;  (5)  heating  zinc  sulphate  and  coal  to  white  heat; 
method,  namely  by  precipitation,  zinc  sulphide  is  a  fine,  white,  amorphous 
sulphide,  sodium  sulphide  or  potassium  sulphide.  Prepared  by  the  last 
method,  namely  by  precipitation,  zinc  sulphide  is  a  fine,  white  amorphous 
powder,  in  which  form  it  is  useful  as  a  pigment;  the  reaction  finds  com- 
mercial application  in  the  manufacture  of  lithophone.  Lithophone  is  a 
double  precipitate  of  zinc  sulphide  and  barium  sulphate.  The  sulphides 
of  the  alkaline  earths,  like  the  sulphides  of  the  alkalies,  throw  down 
zinc  sulphide,  but  in  the  case  of  solutions  of  zinc  sulphate,  the  sulphates 
of  the  earths,  which  are  formed  in  the  reaction,  being  themselves  insoluble, 
go  down  together  with  the  zinc.  Zinc  sulphide  occurs  in  nature  as  a  white 
mineral  (vide  Chapter  VIII)  and  white  may  be  considered  the  true  color 
of  the  compound. 

Zinc  sulphide  is  infusible  and  at  moderate  temperatures  non-volatile,  but 
according  to  Percy  it  volatilizes  at  high  temperatures.  Heated  to  redness  in 
the  air  it  burns  with  the  evolution  of  sulphurous  anhydride  and  the  forma- 
tion of  zinc  oxide,  neutral  zinc  sulphate  (ZnS04),  tetrabasic  sulphate 

148 


CHEMISTRY    OF   THE   COMPOUNDS   OF   ZINC.  149 

(3ZnO,ZnS04)  and  perhaps  other  basic  sulphates  according  to  the  conditions 
under  which  the  oxidation  takes  place.  If  the  sulphates  be  formed  they 
may  be  decomposed  with  evolution  of  sulphurous  anhydride,  sulphuric 
anhydride  and  oxygen  by  further  raising  the  temperature,  so  that  zinc 
oxide  alone  may  be  formed  from  the  sulphide  by  prolonged  roasting  at  the 
proper  temperature.  Zinc  sulphide  may  be  also  converted  into  zinc  oxide 
by  heating  in  an  atmosphere  of  steam,  whereby  hydrogen  sulphide  will  be 
given  off.  Heating  in  a  mixed  atmosphere  of  air  and  steam,  hydrogen  sul- 
phide will  still  be  produced,  but  there  appears  to  be  an  increased  tendency 
to  the  formation  of  zinc  sulphates.  According  to  Schnabel1  the  desul- 
phurization  of  zinc  sulphide  by  means  of  steam  is  incomplete  and  requires 
a  raise  of  temperature  to  white  heat. 

The  behavior  of  zinc  sulphide  in  the  blast  smelting  furnace  does  not 
concern  the  ordinary  method  of  zinc  smelting  at  all  and  is  of  comparatively 
little  importance  in  the  treatment  of  mixed  sulphide  ores.  In  smelting  with 
other  sulphides,  zinc  to  a  certain  extent  enters  the  matte,  making  it  more 
infusible  and  decreasing  its  specific  gravity,  which  are  both  undesirable 
effects.  Indeed,  zinc  is  in  every  respect  an  objectionable  element  in  blast 
furnace  smelting;  and  zinc  as  sulphide  is  worse  than  zinc  as  oxide.  Zinc 
sulphide  is  sometimes  found  in  slags  from  the  lead  blast  furnace,  in  which 
it  is  probably  held  mechanically.  For  further  particulars  as  to  this  subject 
reference  should  be  made  to  Professor  H.  0.  Hof man's  excellent  treatise 
on  the  Metallurgy  of  Lead,  and  to  papers  by  Doctor  M.  W.  lies  in  recent 
numbers  of  the  School  of  Mines  Quarterly. 

Percy  reported  that  in  heating  zinc  sulphide  with  carbon,  or  in  carbon- 
lined  crucibles,  it  was  completely  volatilized;  except  if  it  were  ferruginous 
a  residue  of  iron  sulphide,  free  from  zinc,  remained.  It  was  not  stated  in 
what  form  the  zinc  was  volatilized,  whether  as  ZnS  or  as  Zn,  and  the 
phenomenon  requires  further  investigation  to  determine  the  conditions, 
chemical  and  pyrometric,  under  which  it  takes  place.  According  to- 
Berthier,2  zinc  sulphide  heated  with  carbon  and  lime  yields  metallic  zinc 
and  calcium  sulphide,  but  the  reaction  is  incomplete  and  dependent  upon  the 
temperature.  In  heating  6-32  g.  of  CaC03  with  6-03  g.  of  ZnS  to  a  high 
temperature  more  than  five-sixths  of  the  zinc  was  volatilized,  and  the  residue 
weighing  4-6  g.  contained  only  a  little  ZnS.  Percy  heated  35  g.  of  blende 
with  35  g.  of  lime  to  white  glow  in  a  lime  crucible  (set  inside  a  graphite 
crucible)  and  obtained  a  brown,  porous,  partially  fused  mass  weighing  27  g., 
which  contained  some  calcium  polysulphide,  soluble  in  hot  water,  while  the 
remainder  was  soluble  in  HC1,  hydrogen  sulphide  being  given  off  and 

1Handbuch  der  Metallhiittenkunde,  II,  10.  .    *Tr.  de  Essais,  II,  570. 


150  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

zinc  being  found  in  the  solution.  Iron  also  decomposes  zinc  sulphide  at 
bright  red  heat,  forming  zinc  vapor  and  ferrous  sulphide,,  which  reaction 
is  possibly  of  considerable  importance  in  the  commercial  distillation  of  zinc 
ore.  The  behavior  of  zinc  sulphide  with  carbon,  lime  and  iron  at  high  tem- 
peratures is  of  especial  interest,  inasmuch  as  experience  has  demonstrated 
the  need  of  eliminating  the  sulphur  from  the  ore  as  completely  as 
"possible,  involving  an  unusually  careful  and  laborious  roasting,  because 
whatever  zinc  remains  combined  with  sulphur  is  supposed  to  be  lost  in  the 
process  of  distillation,  being  wasted  in  the  residues  withdrawn  from  the 
retorts.  Carbon  is  necessarily  always  present  in  the  charge  for  distillation ; 
lime  occurs  frequently;  and  metallic  iron  is  often  formed  in  the  process. 
The  fact  that  sulphur  does  actually  hold  back  zinc  in  the  charge  leads  to 
the  inference  that  although  iron  and  lime  may  decompose  zinc  sulphide 
under  certain  conditions,  they  do  not  do  so,  or  at  the  most  their  effect  13 
insignificant,  under  the  conditions  which  prevail  in  the  retort"*during  the 
distillation  of  a  charge.  Opinions  differ,  however,  as  to  this ;  in  reality  the 
nature  of  the  complete  chain  of  reactions  which  take  place  in  the  retort  is 
only  imperfectly  understood. 

Zinc  sulphide  and  zinc  oxide  also  react  under  some  conditions.  According 
to  Berthier,  they  unite  in  various  proportions  under  the  influence  of  heat, 
forming  fusible  oxysulphurets.  Percy  thought  on  the  other  hand  that 
zinc  oxide  was  reduced  by  zinc  sulphide  at  high  temperature,  forming  zinc 
and  sulphurous  anhydride,  by  a  reaction  analogous  to  that  which  takes 
place  between  cuprous  oxide  and  sulphide.  Percy's  experiments  were  incon- 
clusive, however,  and  according  to  Schnabel  (op.  cit.)  attempts  to  effect 
the  reduction  of  zinc  sulphide  by  zinc  oxide  and  carbon  have  failed  on 
account  of  the  incomplete  reaction  between  the  oxide  and  sulphide.  The 
subject  was  brought  up  not  long  ago  by  a  patent  granted  to  Christopher 
James,  of  Swansea,  for  a  process  based  upon  this  reaction.  If  the  reaction 
occurs  at  all  it  must  be  at  a  temperature  higher  than  that  which  prevails  in 
roasting  zinc  blende  in  practice,  since  otherwise  a  larger  amount  of  zinc 
would  be  lost  by  volatilization  than  is  actually  the  case.  In  roasting  blende 
in  practice  a  temperature  of  900°  C.  and  upward  is  attained,  but  with  proper 
furnaces  and  well  conducted  operations  the  loss  of  zinc  is  insignificant. 

Zinc  sulphide  and  lead  oxide  when  mixed  in  the  proper  proportions  and 
heated,  according  to  Berthier,1  react  with  the  formation  of  zinc  oxide,  lead 
and  sulphurous  anhydride.  In  heating  a  mixture  of  24-08  g.  of  blende  with 
55-78  g.  of  litharge  there  were  obtained  29-2  g.  of  impure  lead,  which  con- 
te;<ned  1*8%  S  and  0-8%  Zn.  Over  the  lead  there  was  a  mass  of  zinc  and 

..   I.  403. 


CHEMISTRY    OF   THE   COMPOUNDS   OF   ZINC.  1 

lead  sulphides  and  oxides.  In  order  that  the  zinc  oxide  produced  should 
be  dissolved,  an  excess  of  25%  its  weight  in  litharge  was  requisite,  under 
which  condition  a  resinous  hrown,  glassy  slag  was  obtained.  Metallic  lead 
has  little  effect  on  zinc  sulphide,  if  any  at  all. 

Antimony  does  not  decompose  zinc  sulphide.  Tin  decomposes  it  par- 
tially at  bright  red  heat.  Copper  decomposes  it  at  white  heat  with  the 
formation  of  copper  sulphide.  Copper  protoxide  also  decomposes  it,  but 
incompletely,  forming  a  regulus  of  the  appearance  of  copper  and  copper 
sulphide.  These  investigations  are  due  to  Percy. 

Carbonic  acid  has  no  effect  on  zinc  sulphide,  not  even  at  red  heat,  but  at 
that  temperature  the  carbonates  of  the  alkalies  react  with  it,  forming  zinc 
oxide,  zinc  sulphate,  and  alkaline  sulphides.  Zinc  sulphide  heated  with 
potassium  nitrate  yields  zinc  oxide  and  potassium  sulphate;  possibly  a 
similar  reaction  occurs  between  zinc  sulphide  and  sodium  nitrate. 

According  to  Berthier,1  hydrogen  has  no  action  on  zinc  sulphide,  but 
Morse  states2  that  when  the  latter  is  heated  in  a  current  of  hydrogen  it 
appears  to  sublime/ which  is  explained  by  the  theory  that  the  sulphide  of 
zinc  is  reduced  by  an  excess  of  hydrogen  with  the  formation  of  hydrogen 
sulphide,  and  at  a  lower  temperature  the  volatilized  zinc  recombines  with 
the  sulphur  of  the  H2S. 

Zinc  sulphide  is  insoluble  in  water,  but  it  is  decomposed  and  dissolved 
by  dilute  mineral  acids.  Xitric  acid  is  the  best  solvent.  When  heated  with 
concentrated  sulphuric  acid,  zinc  sulphate  is  formed  together  with  sul- 
phurous anhydride  and  free  sulphur.  Chlorine  vapor  or  water  attacks  zinc 
sulphide  feebly,  but  at  moderately  high  temperatures  chlorine  gas  acts  upon 
it  more  energetically  with  the  formation  of  zinc  chloride  and  sulphur  mono- 
chloride,  according  to  the  reaction 

2ZnS-f-6Cl=:2ZnCl2+S2Cl2. 

Above  600°  C.  the  decomposition  becomes  more  active  and  according  to 
E.  A.  Ashcroft3  it  is  then  represented  by  the  equation 

ZnS-f-2Cl=ZnCl2-fS. 

At  the  temperature  of  600°  C.  and  over  the  monochloride  of  sulphur 
probably  could  not  exist. 

Zinc  sulphide  is  decomposed  by  an  aqueous  solution  of  PbCl2  with  the 

1  Annales  des  Mines.  XI.  46.  by  the  Phoenix  Process,  read  before  the  In- 

'Chem.  Ztg.,  1889,  p.  170.  stitution  of  Mining  and  Metallurgy,  London, 

'  In  a  paper  on   Sulphide  Ore  Treatment       June  19,  1901. 


152  PRODUCTION    AND   PROPERTIES    OF    ZINC. 

formation  of  zinc  chloride  and  lead  sulphide.  On  the  other  hand  lead 
sulphide  is  decomposed  by  molten  zinc  chloride.1 

SULPHITES. — With  sulphurous  acid  zinc  forms  two  sulphites,  namely  an 
acid  and  a  neutral  salt,  known  respectively  as  the  bisulphite  and  the  mono- 
sulphite.  There  are  also  an  hyposulphite  and  a  thiosulphite  of  zinc,  whicli 
are  unstable  compounds  formed  with  hyposulphurous  acid  (H2S02)  and 
thiosulphuric  acid  (H2S203). 

The  neutral  sulphite  of  zinc  (ZnS03)  is  formed  by  the  action  of  E^SO^ 
on  zinc  or  zinc  oxide,  thus: 

H2S03+Zn=2H+ZnS03, 
H2S03+ZnO=:H20-fZnS03. 

In  the  case  of  the  former  reaction,  the  hydrogen  which  is  set  free  reacts 
with  sulphurous  acid,  thus : 

H2S03+2H=H2S02+H20. 

The  hyposulphurous  acid  combines  with  zinc  as  hyposulphite,  which  is 
altered  first  to  thiosulphite  and  then  to  sulphite. 

Zinc  oxide  dissolved  in  H2S03  furnishes  small  crystals,  but  little  soluble 
in  water  and  insoluble  in  alcohol,  which  correspond  to  the  symbol 
ZnS03+2H20,  or  to  2ZnS03+5H20.  This  compound  is  precipitated  from 
its  aqueous  solution  by  alcohol,  but  it  dissolves  readily  in  an  excess  of 
H2S03.  Exposed  to  the  air  zinc  sulphite  changes  to  sulphate.  At  200°  C. 
zinc  sulphite  loses  its  sulphurous  anhydride,  zinc  oxide  remaining.  At  a 
higher  temperature  the  desulphurization  takes  place  rapidly  and  completely ; 
the  escape  of  the  gas  causes  tho  precipitate  to  become  very  porous  and  light, 
swelling  enormously  in  bulk. 

Zinc  sulphite  is  barely  soluble  in  water,  but  in  the  presence  of  sul- 
phurous acid  it  forms  a  solubl  i  acid  salt,  which  is  represented  probably  by 
the  symbol,  H2ZnS206==ZnS03,H2S03,  which  may  be  considered  a  solution 
of  the  monosulphite  in  an  excess  of  sulphurous  acid.  Whichever  be  the 
correct  view,  sulphurous  acid  can  be  driven  off  by  boiling  the  solution  and 
insoluble  zinc  monosulphite  precipitated  thereby.  Zinc  hydroxide  is  pre- 
cipitated from  a  solution  of  zinc  sulphite  by  means  of  milk  of  lime,  calcium 
bisulphite  being  formed  and  going  into  solution. 

The  properties  of  zinc  sulphite  are  of  importance  in  several  processes 
proposed  for  the  treatment  of  mixed  sulphide  ores,  and  for  the  neutraliza- 
tion of  sulphurous  fumes. 

1S.  Ganelin,  United  States  patent  No.  593,415,  Nov.  fl.  1807. 


CHEMISTRY   OF   THE    COMPOUNDS    OF   ZINC. 


153 


SULPHATES. — Zinc  forms  numerous  sulphates,  in  general  by  the  action 
of  sulphuric  acid  on  the  metal,  its  oxide  and  carbonates,  or  by  roasting  the 
sulphide,  the  nature  of  the  salt  obtained  varying  with  the  conditions  of  its 
production. 

The  simple  or  neutral  sulphate  of  zinc  is  represented  by  the  symbol 
ZnS04=ZnO,S03.  When  obtained  by  crystallization  from  a  solution  it  is 
combined  with  varying  proportions  of  water  according  to  the  temperature 
at  which  it  is  crystallized.  The  ordinary  zinc  sulphate  of  commerce  is 
represented  by  the  symbol  ZnS04+7EE20. 

ZnS04-{-7H20  is  obtained  by  crystallization  from  solutions  below  30°  C., 
forming  as  orthorhombic  prisms,  isomorphous  with  magnesium  sulphate, 
and  of  2-036  sp.  gr.  It  is  insoluble  in  absolute  alcohol,  but  is  extremely 
soluble  in  water.  The  aqueous  solution  has  an  acid  reaction  and  a  styptic, 
metallic  taste.  According  to  Poggiale1  the  solubility  of  ZnS04  and 
ZnS04,7H20  in  100  parts  of  water  is  as  follows: 


Temperature 

ZnSO4,7HaO 

ZnSO< 

Temperature 

ZnSO4)7H8O 

ZnSO4 

to°  c. 

115-22 

43-02 

60 

313-48 

74-20 

10 

138-21 

48-36 

70 

369-36 

79*25 

20 

161-49 

53-13 

80 

442-62 

84-60 

30 

190-90 

58-40 

90 

532-02 

89-78 

40 

224-05 

63-52 

100 

653'59 

05  03 

50 

263-84 

68-75 

Gerlach2  and  Schiff3  give  the  following  data  as  to  specific  gravity  in  con- 
nection with  which  I  have  interpolated  the  columns  of  percentage  of  ZnS04 
and  the  corresponding  approximate  readings  on  the  Beaume  and  Twaddell 

scales : 


Gterlach'a  determinations  at  15°  C. 

SO4.7H20 
Per  cent. 

ZnS04 
Per  cent. 

Schiff's  deter- 
minationi 

of  sp.  gr.  at 
20-5%  C. 

Sp.  gr. 

Degrees  Beaume. 

Degrees 
Twaddell. 

United  St  ite^ 

Europe. 

IA 
15 
20 
25 
30 
35 
40 

2-8 
5-6 
8-4 
11-2 
14-0 
16-8 
19-6 
22-5 

1-0288 
1-0593 
1:0905 
1-1236 
1-1574 
1-1933 
1-2315 
1-2709 

4-1 
8-2 
12-1 
16-0 
19-8 
23-4 
27-2 
30-9 

4-0 
8-0 
12-0 
15-9 
19-6 
23-2 
27-0 
30-7 

5'8 
11-8 

18-2 
24-8 
31-5 
39-5 
46-2 
54-2 

1-0289 
1-0588 
1-0899 
1-1222 
1-1560 
1-1914 
1-2285 
1-2674 

45 

25-3 

1-3100 

34-3 

34-2 

62-0 

1  '  3083 

50 

28-1 

1  '  3532 

37-8 

37-6 

70-6 

1-3511 

55 

30-9 

1  '  3986 

41-2 

41-0 

79-4 

1-3964 

60 

33-7 

1-4451 

44-7 

44-4 

89-0 

1  '  4439 

1Ann.  de  Chimie  et  Physique  (3),  VIII,  467.     2  Fresenius'  Zts.  f.  analyt.  Chem.,  VIII,  260. 
3  Liebig's  Annalen  der  Chemie,  CX,  72. 


154  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

The  aqueous  solution  of  zinc  sulphate  is  decomposed  by  the  electric 
current,  metallic  zinc  being  deposited  at  the  cathode  while  the  acid  radical 
is  set  free  at  the  anode. 

Zinc  sulphate  crystallized  with  seven  molecules  of  water  effloresces  on 
exposure  to  the  atmosphere ;  it  loses  six  molecules  of  its  water  of  crystalliza- 
tion at  100°  C.,  and  the  remaining  molecule  at  200°.  It  is,  however, 
difficult  to  dehydrate  the  salt  completely  without  driving  off  sulphuric 
anhydride. 

ZnS04-r-GH20  is  produced  by  crystallization  at  30°  C.,  forming  in 
clinorhombic  crystals.  It  is  also  produced  by  driving  off  one  molecule  of 
water  from  the  compound  previously  described. 

ZnS04+5H20  is  obtained  by  crystallization  between  40°  and  50°  C.; 
also  by  heating  the  septihydrated  salt  with  alcohol  of  0-856  sp.  gr. 

ZnS04+4H20  is  produced  together  with  the  septihydrated  salt  when  an 
acid  and  concentrated  solution  is  made  to  crystallize  at  0°,  forming  as  opaque 
rhombohedrons,  which  are  unaltered  by  exposure  to  air. 

ZnS04-f-2H20  is  deposited  by  the  addition  of  concentrated  H2S04  to  a 
boiling  solution  of  ZnS04;  it  is  a  crystalline  powder.  It  is  also  produced 
by  boiling  the  septihydrated  salt  with  absolute  alcohol. 

ZnS04-|-H20  is  produced  by  heating  the  septihydrated  salt  to  100°  C. 
It  is  also  deposited  in  crystalline  grains  from  a  saturated  solution  at  100°  C. 
According  to  Graham  this  salt  does  not  lose  its  water  until  238°  C. 

ZnS04,  the  anhydrous  salt,  is  a  white,  brittle  substance  of  34  sp.  gr.  It 
absorbs  moisture  from  the  air,  transforming  itself  into  ZnS04+7H20,  and 
in  combining  with  water  disengages  heat.  It  is  formed  by  roasting  zinc 
sulphide  at  a  low  temperature.  At  a  higher  temperature  it  is  decomposed 
with  the  formation  of  a  basic  sulphate,  oxide,  sulphuric  anhydride,  sulphur- 
ous anhydride  and  oxygen.  Calcined  in  a  current  of  hydrogen  it  leaves  a 
residue  of  zinc  oxysulphuret. 

The  decomposition  of  ZnS04  by  a  simple  calcination  is  a  tedious  opera- 
tion, requiring  a  high  temperature,  and  it  has  been  proposed  to  facilitate  it 
by  calcining  with  a  mixture  of  carbon,  when  under  certain  conditions  of 
temperature  the  reaction  ZnS04+C=ZnO-fS02+CO  takes  place.  Such 
a  calcination  is  of  course  limited  practically  below  the  temperature  at 
which  ZnO  is  reduced  by  carbon.  In  fact,  this  reaction  takes  place  only  at 
dull  red  heat.1  If  zinc  sulphate  mixed  with  carbon  be  raised  quickly  to 
white  heat  the  sulphate  is  reduced  to  sulphide.  Zinc  sulphate  is  also  de- 
composed by  roasting  in  a  closed  vessel  with  the  equivalent  quantity  of  zinc 

1  P.  Mahler,  Annales  des  Mines,  1885,  VII,  512. 


CHEMISTRY    OF    THE    COMPOUNDS    OF    ZLNTC.  155 

sulphide,   according  to  the  reaction   ZnS+3ZnS04=4ZnO+4S02.     This 
reaction  was  employed  on  a  large  scale  in  the  Parnell  process. 

The  following  experiments  made  by  me  several  years  ago  are  not  without 
interest,  although  the  temperatures  were  not  determined  accurately;  the 
calcinations  were  performed  in  the  muffle  of  an  ordinary  assay  furnace : 

I.  Ten  grams  of  anhydrous  zinc  sulphate  were  calcined  at  orange  heat 
(estimated  to  be  900°  C.)  for  one  hour.     The  product  contained  2-68%  S. 
Roasting  for  another  hour  at  the  same  temperature  eliminated  all  the  sul- 
phur. 

II.  Ten  grams  of  ZnS04  were  calcined  at  dull  red  heat  (estimated  to  be 
700°  C.)  for  two  hours.    The  product  contained  14-78%  S. 

III.  Ten  grams  of  ZnS04  mixed  with  one  gram  of  charcoal  were  roasted 
contemporaneously  in  the  same  muffle  and  for  the  same  length  of  time  as 
in  experiment  II.     The  product  contained  9-58%  S. 

IV.  Four  gramsj  of  ZnS  and  the  equivalent  of  ZnS04  were  heated  for 
1  h.  10  m.  in  a  covered  crucible,  first  at  cherry-red,  which  was  raised  gradu- 
ally to  orange  heat.     The  product  contained  0-76%  S. 

ZnS04,ZnO:  The  bibasic  sulphate  of  zinc  is  obtained  by  digesting  a 
solution  of  ZnS04  with  an  equivalent  quantity  of  ZnO  or  ZnO,H20  (pre- 
pared by  precipitation  from  an  equal  quantity  of  ZnS04  solution).  The 
solution  of  this  salt,  the  bibasic  sulphate,  can  not  be  crystallized,  but  can  be 
decomposed  by  prolonge'd  boiling. 

ZnS04,3ZnO :  Slow  evaporation  of  a  solution  of  the  bibasic  sulphate,  as 
well  as  an  addition  of  water  to  it,  produces  the  tetrabasic  sulphate,  which 
presents  itself  as  flexible,  quadrangular,  needle-shape  crystals,  retaining  10 
molecules  of  water.  The  tetrabasic  sulphate  is  produced  also  by  the  incom- 
plete precipitation  of  a  solution  of  the  neutral  sulphate  by  means  of  potash 
and  dissolving  the  precipitate  in  boiling  water.  Upon  cooling,  the  tetra- 
basic sulphate  is  deposited  as  small,  unctuous  crystals,  retaining  2H20. 
The  tetrabasic  sulphate  is  produced,  moreover,  by  the  prolonged  digestion 
of  the  neutral  sulphate  with  an  excess  of  zinc,  or  or  zinc  oxide,  which  affords 
the  salt  with  10H20  in  opaque  laminae  or  needles.  The  same  salt  can  be 
obtained  by  partially  decomposing  the  neutral  sulphate  by  heat  and  taking 
up  the  residue  by  boiling  water.  The  tetrabasic  sulphate  with  10H20 
dcssicates  slowly,  forming  a  powder  which  is  unaltered  by  the  air.  It  loses 
8H20  between  100°  and  125°  C.  and  retains  2H20  (Schindler),  but 
according  to  Kuhn  the  salt  dried  above  100°  contains  4H20  and  the  air 
dried  salt,  8H20.  According  to  Biischer  a  compound  with  7H20  is  obtained 
when  20  parts  of  borax  in  aqueous  solution  is  added  to  a  solution  containing 
60  parts  of  ZnS04  at  50°  to  60°  C. ;  the  precipitate  is  free  from  boric  acid. 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 

The  tetrabasic  sulphate  of  zinc  is  supposed  to  be  the  form  of  basic 
sulphate,  which  is  produced  chiefly  in  roasting  the  neutral  sulphate  at  the 
temperature  at  which  the  latter  decomposes.  At  still  higher  temperature 
the  tetrabasic  sulphate  itself  is  decomposed,  forming  ZnO,  S03,S02  and  0. 

Tetrabasic  sulphate  of  zinc  is  insoluble  in  cold  water  and  but  little  soluble 
in  boiling  water. 

ZnS04,5ZnO-f-10H20 :  The  hydrated  hexabasic  sulphate  of  zinc  is  a 
white  powder,  which  is  formed  by  the  action  of  water  on  the  sulphate  of  zinc 
and  ammonium  (ZnS04[NH3]2+H20).  It  loses  its  water  at  100°,  and 
regains  subsequently  only  about  a  third  of  it  in  the  air. 

ZnS04,7ZnO+2H20  :  The  hydrated  octobasic  sulphate  of  zinc  is  precipi- 
tated by  the  addition  of  a  large  quantity  of  water  to  the  bibasic  salt.  It 
forms  a  voluminous  precipitate,  which  after  drying  is  very  light.  It  is 
insoluble  in  water.  Digested  with  a  solution  of  the  neutral  sulphate  it 
forms  tetrabasic  sulphate.  The  octobasic  sulphate  with  2H20  is  also  obtained 
by  boiling  a  solution  of  neutral  sulphate  supersaturated  with  ammonia. 

ZnS04,H2S04-f-8H20 :  Von  Kobell  reported1  the  existence  of  an  acid 
sulphate  of  zinc,  obtained  accidentally,  as  limpid,  clinorhombic  prisms, 
soluble  in  boiling  water,  but  only  slightly  in  cold  water. 

OXIDES. — Zinc  is  commonly  considered  as  forming  only  one  oxide,  namely 
ZnO,but  recently  Robert  C.  Schuepphaus  (in  conjunction  with  E.  Lungwitz) 
has  pointed  out  the  possibility  of  the  existence  of  a  lower,  or  at  all  events 
another,,  oxide.  The  known  existence  of  a  suboxide  of  cadmium,  Cd20, 
points  by  analogy  to  the  possibility  of  the  existence  of  a  similar  suboxide  of 
zinc.  The  possibility  that  there  is  a  dioxide,  Zn02,  has  also  been  pointed  out. 

Zinc  oxide  (ZnO)  exists  in  nature  as  the  mineral  zinkite,  or  red  zinc  ore, 
which  is  found  in  considerable  quantity  in  New  Jersey,  but  is  not  elsewhere 
abundant.  It  nlay  be  prepared  artificially  (1)  by  oxidizing  metallic  zinc; 

(2)  by  roasting  zinc  sulphide,  zinc  sulphite  and  the  various  sulphates;  and 

(3)  by  heating  the  carbonates,  nitrates,  hydrates  and  various  other  salts.    In 
the  previous  chapter  the  conditions  under  which  metallic  zinc  is  oxidized 
by  the  atmosphere  were  described.     The  oxidation  of  the  metal  is  also 
effected  by  heating  with  various  salts  which  can  supply  oxygen,  such  as 
potassium  chlorate  and  nitrate  and  arsenic  acid. 

Zinc  oxide  is  normally  a  white  powder  of  5-5  to  5*7  sp.  gr.,  which  upon 
heating  acquires  a  canary  yellow  color  and  upon  cooling  again  regains  its 
former  appearance.  It  undergoes  no  chemical  change  in  this  procedure  and 
is  regarded  as  a  permanent  compound,  for  which  reason  and  the  ease  of 

1  Journ.  f.  prakt.  Them..  XXVIII,  492. 


CHEMISTRY    OF   THE    COMPOUNDS   OF   ZINC. 


obtaining  it  pure  it  is  commonly  used  as  the  standard  for  the  solutions 
employed  in  determining  zinc  in  analytical  chemistry. 

In  its  pyrometallurgical  behavior  zinc  oxide  is  infusible  and  is  com- 
monly regarded  as  non-volatile,  but  that  idea  is  incorrect.  Zinc  oxide  is 
certainly  non-volatile  at  moderate  temperatures  and  to  only  a  slight  extent 
at  those  which  are  attained  in  the  roasting  furnace  (where  the  maximum 
is  about  1000°  C.)  but  according  to  experiments  of  Stahlschmidt1  it  is  not- 
ably volatile  at  the  melting  point  of  silver  (970°  C.,  Holman),  about  15% 
more  at  the  melting  point  of  copper  (1054°  C.,  Eoberts- Austen)  and  rapidly 
at  white  heat.  Roasted  blende  is  not  volatile  at  the  melting  point  of  silver, 
but  is  considerably  volatile  at  that  of  copper. 

Zinc  oxide  is  reduced  at  high  temperatures  by  various  substances,  among 
them  carbon  and  carbon  monoxide  and  upon  that  reaction  is  based  the  most 
important  process  in  the  practical  metallurgy  of  zinc.  The  reduction  of 
zinc  oxide  by  carbon  and  carbon  monoxide  is  express  by  the  formulae : 


(1)  ZnO+C=Zn-fCO  and  (2)  ZnO+CO=Zn-j-CO, 


The  precise  nature  of  the  reaction  which  actually  takes  place  in  the 
reduction  and  distillation  on  a  large  scale,  whether  it  be  according  to  equa- 
tion No.  1  or  equation  No.  2,  or  both,  is  unknown.  Whatever  it  be,  it  is 
found  necessary  in  practice  to  have  a  large  excess  of  carbon  in  the  retort. 
That  excess  of  carbon  among  other  purposes  serves  to  reduce  to  monoxide 
such  carbon  dioxide  as  may  be  formed,  which  otherwise  might  act  oxidiz- 
ingly  on  the  zinc  (the  reduction  of  carbonic  dioxide  by  zinc  taking  place  at 
red  heat),  while  any  zinc  oxide  which  may  perchance  have  been  formed  is 
reduced  again  by  carbon  or  carbon  monoxide,  either  or  both.  The  net  result, 
irrespective  of  what  actually  occurs,  is  zinc  vapor  and  carbon  monoxide, 
which  alone,  or  practically  alone,  issue  from  the  retort,  when  there  is  an 
excess  of  carbon  present.  Schnabel  remarks2  that  in  the  case  of  a  mixture  of 
carbon  monoxide  and  dioxide  the  amount  of  zinc  oxidized  by  the  latter  is 
dependent  upon  its  proportion  in  the  mixture  and  the  temperature. 

The  reduction  of  zinc  oxide  by  carbon  or  carbon  monoxide  begins  accord- 
ing to  recent  experiments  by  Robert  C.  Schuepphaus  and  E.  Lungwitz3  at 
910°  C,  a  statement  which  is  confirmed  by  Hempel*  who  says  that  reduc- 
tion begins  under  the  boiling  point  of  zinc  (920° ) .  It  is  completed  at  about 
1,300°  C.,  a  temperature  which  is  commonly  attained  in  practical  distilla- 
tion. The  comparatively  low  temperature  at  which  the  reduction  begins, 

1Berg-u.  Huttenm.  Ztg.,  1875,  p.  69.  3  Journ.  Soc.  Chem.Ind..  Nov.  30, 1899,p.987, 

2  FTandbuoh  der  Metallhiittenkunde,  II,  7.  *Berg-u.  Huttenm.  Ztg.,  1893,  No*.  41  and  42. 


158  PRODUCTION   AND  PROPERTIES   OF   ZINC. 

approaching  closely  that  which  is  often  reached  in  the  roasting  furnace 
indicates  the  danger  of  loss  of  zinc  in  the  latter  through  reduction  by 
carbonaceous  matter  in  the  gases  of  combustion;  if  the  roasting  be  done  in 
muffle  furnaces  the  operation  is  of  course  free  from  danger  in  this  respect. 
As  would  be  naturally  expected  the  temperature  and  facility  of  the  com- 
plete reduction  of  zinc  oxide  is  affected  by  the  physical  condition  of  that 
substance.  Very  finely  divided,  pure  oxide,  such  as  is  prepared  by  calcining 
precipitated  zinc  carbonate  is  reduced  quickly  and  completely  at  yellow  heat. 
Zinc  oxide  from  ores  and  in  a  coarser  state  of  subdivision,  on  the  other  hand, 
requires  a  full  white  heat  and  a  longer  time.  It  is  commonly  accepted  that 
zinc  oxide  obtained  by  roasting  zinc  blende  is  more  difficultly  reduced  than 
that  obtained  by  calcining  zinc  carbonate  (smithsonite  and  hydrozinkite), 
but  although  that  conclusion  is  drawn  from  and  supported  by  the  results 
of  practice,  I  am  unaware  that  it  has  been  the  subject  of  accurate  pyro- 
metrical  investigation;  the  difference  in  reducibility  is  probably  due  to 
the  physical  condition  of  the  ores  rather  than  to  inherent  differences  in 
the  chemical  properties  of  the  oxides  obtained  in  the  various  ways. 

Hydrogen  reduces  zinc  oxide  at  red  heat  but  the  steam  produced  by  that 
reaction  may  under  certain  circumstances  reoxidize  the  zinc  to  a  more  or  less 
extent.  Schnabel  (op.  cit.,  p.  7) quotes  experiments  by  Deville1  and  Dick,2 
which  indicated  that  if  small  quantities  of  hydrogen  were  passed  quickly 
over  glowing  zinc  oxide,  chiefly  zinc  was  obtained ;  while  almost  all  the  zinc 
was  reoxidized  if  the  current  of  hydrogen  was  slow.  The  oxidizing  action  of 
steam  on  zinc  may  be  dependent  upon  both  the  proportion  it  bears  to  the 
hydrogen  present,  and  the  temperature.  Deville  was  of  the  opinion  that  the 
latter  played  the  more  important  part,  since  with  a  strong  current  of 
hydrogen  a  decrease  in  temperature  took  place,  which  was  not  the  case  with 
a  weaker  current.  At  the  reduced  temperature,  thus  caused,  the  steam 
cannot  act  oxidizingly  on  the  zinc,  as  it  can  at  the  higher  temperature. 

Metallic  iron  is  said  by  Percy  to  reduce  zinc  oxide  at  high  temperatures. 
Metallic  iron  is  frequently  formed  in  the  retort  during  distillation  of  a 
charge  of  zinc  ore.  The  behavior  of  zinc  oxide  with  zinc  sulphide  has 
been  referred  to  in  a  previous  paragraph.  Sulphur  itself  when  heated  with 
zinc  oxide  produces  zinc  sulphide  and  sulphurous  anhydride. 

Zinc  oxide  fuses  with  carbonates  of  the  alkali  metals,  forming  colorless, 
transparent  substances,3  when  the  proportion  of  ZnO  to  the  carbonate  does 
not  exceed  1 :  4.  The  chemical  nature  of  these  compounds  is  not  described. 
They  are  probably  zincates,  compounds  of  zinc  with  potassium  and  sodium 

1Annales  de  Chimie  et  de  Physique   (3),  XLIII.  479.  2  Percy,  Metallurgy. 

8  Berthier,   Tr.   de  Essais,   II,   567. 


CHEMISTRY   OF   THE    COMPOUNDS    OF   ZINC.  159 

of  that  character  being  formed  under  certain  circumstances  in  hydro- 
metallurgy.  Although  zinc  oxide  is  usually  a  base  it  sometimes  plays  the 
part  of  an  acid,  forming  zincates  with  alumina,  the  alkalies,  and  the  alkaline 
earths.  In  this  respect  zinc  presents  an  analogy  to  beryllium  (a  member  of 
the  same  group  of  elements  according  to  the  periodic  classification)  which 
with  the  alkalies,  alkaline  earths,  etc.,  forms  beryllates.  The  weak  basic 
character  of  zinc  is  shown,  moreover,  in  its  tendency  to  form  basic  salts 
(such  as  basic  sulphates,  carbonates,  etc.)  in  which  it  also  resembles  the 
chemical  behavior  of  beryllium  and  magnesium.  The  strong  bases  do  not 
readily  form  basic  salts,  but  on  the  contrary  form  strong  acid  salts.  Thus 
potassium  and  sodium  form  acid  carbonates;  calcium  forms  preferably  an 
acid  carbonate,  but  it  is  unstable;  beryllium  and  magnesium  form  only 
extremely  unstable  compounds  with  carbonic  acid,  their  basic  properties  not 
being  sufficiently  strong  to  hold  them  in  combination  with  the  weak  acid 
except  at  a  low  temperature.  The  similarly  weak  union  between  zinc  and 
carbonic  acid  is  of  practical  importance  in  the  calcination  of  calamine  ores 
(smithsonite  and  hydrozinkite)  which  process  is  in  all  respects  analogous  to 
that  of  lime  burning.  The  zincate  of  aluminum,  or  zinc  spinel,  occurs  in 
nature  as  the  mineral  gahnite,  and  is  also  formed  in  the  retort  during  dis- 
tillation. Its  properties  are  described  in  a  subsequent  paragraph.  Zinc 
oxide  also  unites  with  the  strong  base  litharge,  lead  oxide,  forming  a  fluid, 
pale  yellow  slag  when  heated  with  eight  times  its  weight  of  litharge,  and  a 
less  fluid  compound  with  a  smaller  proportion  of  litharge,  down  to  the  point 
where  the  mixture  becomes  infusible.1 

Zinc  oxide  combines  with  silica,  forming  silicates,  which  are  described 
under  that  caption. 

With  respect  to  the  hydrometallurgical  properties  of  zinc  oxide,  the 
limits  of  this  treatise  will  permit  of  reference  only  to  those  which  are  of 
practical  importance  in  the  treatment  of  mixed  ores  and  the  production 
of  the  commercial  salts  of  zinc.  Zinc  oxide  is  soluble  in  numerous  acids, 
especially  sulphuric,  chlorhydric  and  nitric,  with  which  it  forms  respectively 
sulphate,  chloride  and  nitrate.  It  is  soluble  also  in  caustic  soda  and  potash, 
forming  zincates,  and  in  ammonium  carbonate  and  ammonia.  Sulphurous 
acid  takes  it  up  as  bisulphite.  Ferric  chloride  and  ferric  sulphate  dissolve 
it  as  chloride  and  sulphate  respectively,  an  equivalent  quantity  of  ferric 
oxide  being  precipitated.  In  water  zinc  oxide  is  quite  insoluble.  It  is 
dissolved  by  acetic  acid  as  acetate.  Zinc  oxide  suspended  in  cold  water 
is  attacked  by  chlorine  gas  passed  into  the  emulsion,  zinc  oxychloride  and 

1  Berthier,  op.  cit,  I,  515. 


160  PRODUCTION  AND  PROPERTIES  OE  ZINC. 

hypochlorite  being  first  formed  and  the  zinc  going  finally  into  solution 
according  to  the  equation  : 


According  to  E.  A.  Ashcroft1  zinc  oxide  is  converted  directly  to  chloride 
by  chlorine  gas  at  a  high  temperature  (upward  of  600°  C.)  according  to  the 
reaction  : 

ZnO+2Cl=ZnCl2+0 

HYDROXIDE.  —  The  hydroxide,  or  hydrate  of  zine  (ZnO,H20—  Zn[OH]2), 
is  produced  as  a  white  amorphous  substance  by  precipitation  from  solutions 
of  zinc  salts  by  caustic  soda  or  caustic  potash,  avoiding  an  excess  of  alkali, 
since  the  precipitate  is  thereby  redissolved,  but  if  once  dried  it  becomes 
less  soluble  in  alkali.  It  is  also  precipitated  by  the  hydrates  of  lime  and 
magnesia.  Zinc  oxide  does  not  unite  directly  with  water.  Hydrate  of  zinc 
is  also  produced  by  the  galvanic  action  between  zinc  and  iron,  brass,  or  lead 
in  an  ammoniacal  solution  of  zinc  oxide.  Zinc  hydrate  is  easily  decomposed 
by  heat  into  the  anhydrous  oxide  and  water.  It  is  soluble  in  acids  and  solu- 
tions of  ammonium  salts  and  the  other  substances  which  are  solvents  for 
zinc  oxide. 

CARBONATES.  —  Zinc  forms  with  carbonic  acid  a  long  series  of  carbonates 
and  hydrocarbonates,  certain  of  which  exist  in  nature  as  the  minerals  smith- 
sonite  and  hydrozinkite.  In  general  they  are  prepared  artificially  by  addi- 
tion of  sodium  or  potassium  carbonate  to  a  neutral  solution  of  a  salt  of 
zinc,  usually  the  sulphate.  Because  of  the  weak  basic  character  of  zinc  as 
an  element  the  basic  carbonates  are  the  more  easily  formed.  The  neutral 
carbonate  of  zinc  cannot  be  obtained  by  precipitation  with  Na2C03  or  K2C(X{ 
under  ordinary  circumstances;  when  either  of  those  salts  is  added  to  a 
neutral  solution  of  a  salt  of  zinc  there  is  a  disengagement  of  carbonic  acid 
and  the  precipitate  formed  is  a  basic  hydrocarbonate.  This  hydrocarbonate 
is  soluble  in  an  aqueous  solution  of  carbonic  acid;  upon  exposure  to  the  air 
a  granular  powder  deposits  from  the  solution,  which  has  been  taken  for 
neutral  carbonate  of  zinc  by  some  chemists,  but  by  others  has  been  held  to  be 
a  basic  carbonate.  According  to  Thorpe2  neutral  zinc  carbonate,  ZnC03,  can 
be  produced  artificially  by  adding  acid  carbonate  of  sodium  to  a  solution 
of  zinc  sulphate,  while  Eoscoe  and  Schorlemmer  state  that  it  is  produced 

;by  precipitation  from  ZnS04  with  an  excess  of  hydrogen  potassium  car- 

l'i    ; 

1  In  a  paper  on  Sulphide  Ore  Treatment,        Metallurgy,  London,  June  19,  1901. 
read  before   the   Institution   of  Mining  and  2  Dictionary  of  Applied  Chemistry,  p.  1057. 


OIIKMFSTKY    OF    THE    COMPOUNDS    OF    ZINC.  161 

bonate  (KHC03),  the  neutral  carbonate  of  sodium  (N"a2C03)  throwing 
down  a  basic  carbonate  of  zinc,  which  is  the  more  basic  the  higher  the  tem- 
perature of  precipitation  and  the  more  dilute  the  solution. 

Zinc  carbonate,  ZnC03,  is  produced  when  the  solution  of  a  zinc  salt  is 
precipitated  by  an  alkaline  carbonate  under  pressure.  As  obtained  by  heat- 
ing a  solution  of  ZnCL  to  150-160°  C.  and  precipitating  with  calcium 
carbonate  or  sodium  bicarbonate  it  is  a  white  microcrystalline  powder.  The 
neutral  hydrated  carbonate  (2ZnC03,H20)  is  an  amorphous  powder 
obtained  by  digesting  a  basic  carbonate  of  zinc  with  ammonium  bicarbonate. 
The  anhydrous  carbonate  of  zinc  is  soluble  in  carbonic  acid  water.  A 
solution  of  C02  at  five  atmospheres,  taking  up  1/189  its  own  weight  of 
ZnC03.  On  exposure  to  the  air  the  solution  becomes  turbid,  and  on  boiling 
a  precipitate  of  zinc  hydrocarbonate  comes  down. 

The  basic  carbonates  and  basic  hydrocarbonates  of  zinc  are  the  more 
important  compounds  of  zinc  and  carbonic  acid.  They  are  formed  in  the 
manner  previously  described.  Their  precise  composition  depends  upon 
the  conditions  under  which  they  are  precipitated.  All  of  these  com- 
pounds lose  their  water  and  their  carbonic  acid  at  300°  C.1  There  is  a  long 
list  of  them  and  the  following  is  probably  only  partially  complete : 

2ZnC03,Zn(OH)2:  This  is  the  precipitate  formed  by  adding  an  excess 
of  alkaline  bicarbonate  to  a  solution  of  ZnS04  (Rose,  Poggend.  Ann.  LXXV, 
107;  Ann,  de  Chimie  et  de  Physique  (3)  XLII,  106). 

ZnC03,Zn(OH)2-f  2H20 :  This  is  a  thin,  white  powder  obtained  by  pre- 
cipitating cold  a  solution  of  ZnS04  with  sodium  sesquicarbonate,  washing 
with  water  and  drying  in  the  air  (Boussingault,  Ann.  de  Chimie  et  de 
Physique  (2)  XXIX,  284).  When  the  precipitation  takes  place  from  hot 
solutions,  the  precipitate  holds  only  one  molecule  of  H20  (Schindler). 

2ZnC03,3Zn(OH)2:  Produced  by  the  precipitation  cold  of  a  zinc  solu- 
tion by  means  of  a  neutral  alkaline  carbonate.  A  certain  quantity  of  zinc 
carbonate  remains  dissolved  by  the  carbonic  acid  set  free  in  the  solution,  but 
is  brought  down  by  boiling.  The  precipitate  generally  entrains  some  alkali. 
H  a  boiling  solution  of  ZnS04  be  poured  into  a  boiling  solution  of  an 
alkaline  carbonate  the  precipitate  comes  down  as  a  light  powder  resembling 
magnesia ;  if  the  boiling  be  continued  for  some  time,  the  precipitate  is  made 
free  from  alkali  and  the  precipitation  is  complete.  If  the  precipitation  is 
effected  by  ammonium  carbonate  the  precipitate  is  crystalline.  This  hydro- 
carbonate  is  soluble  in  2,000  to  3,000  parts  of  cold  water,  separating  out 
upon  boiling,  and  also  in  solutions  of  ammonium  salts,  from  which  it 

1  According  to  Rose,  who  states  that  zinc  carbonates  slowly  decompose  at 
this  temperature. 


162  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

disengages  ammonia  by  boiling.  According  to  Bensdorff  it  is  this  hydro- 
carbonate  which  forms  the  coating  on  sheet  zinc  exposed  to  air  under  a  film 
of  water.  When  dried  at  100°  C.,  this  compound  [2ZnCO:{,3Zn(OH)2~] 
becomes  4ZnC03,7Zn(OH)2-fH20. 

3ZnC03,5Zn(OH)2-fH20:  According  to  Lefort  (Journ.  Pharm.  (2) 
XI,  329)  the  precipitates  produced  by  alkaline  carbonates  from  zinc  solu- 
tions, hot  or  cold,  have  this  composition.  Schindler  considers  that  the 
precipitate  described  above  as  2ZnC03,3Zn(OH)2  is  more  accurately 
represented  by  the  formula  3ZnC03,5Zn(OH)2-f  H26. 

ZnC03,5Zn(OH)2+H20:  This  is  the  natural  carbonate— i.e.,  the  min- 
;eral  zinconise  or  hydrozinkite.  Lefort  attributes  the  same  composition  to 
precipitates  brought  down  cold  by  alkaline  bicarbonates ;  while  H.  Rose 
ascribed  it  to  that  obtained  from  neutral  carbonates  and  very  dilute  zinc 
solutions,  hot  or  cold. 

ZnC03,3ZnO-|-2H20 :  This  is  the  precipitate  produced  by  sodium  car- 
bonate and  the  tetrabasic  sulphate  of  zinc. 

ZnC03,7ZnO-}-2H20 :  Obtained  from  sodium  carbonate  and  the  octobasic 
sulphate  of  zinc. 

CHROMATE. — Zinc  chromate,  ZnCr04,  is  made  by  precipitation  of  a  solu- 
tion of  zinc  sulphate  with  neutral  potassium  chromate.  If  the  solution  is 
alkaline,  zinc  hydroxide  is  precipitated  also;  hence  the  method  needs  much 
care.  Potassium  bichromate  cannot  be  used  because  of  the  ready  solubility 
of  zinc  chromate  in  free  acid.  Zinc  chromate  can  be  prepared,  however,  by 
boiling  zinc  oxide  with  potassium  bichromate.  Zinc  chromate  is  used  as  a 
pigment,  having  a  light  lemon  color,  which  is  permanent.  It  is  not  affected 
by  sulphur,  and  can  be  mixed  with  other  pigments.  It  is  very  soluble  in 
mineral  acids,  and  is  decomposed  by  caustic  alkalies. 

SILICATES. — Zinc  combines  with  silica  in  various  proportions.  The 
formula,  Zn2Si04(=2ZnO,Si02),  represents  the  singulo-silicate,  in  which 
form  it  occurs  in  nature  as  the  minerals  willemite  and  hemimorphite.  The 
other  silicates  of  zinc  correspond  to  the  usual  formulae — i.e.,  ZnO,Si02=the 
bisilicate,  etc.  These  silicates  are  prepared  artificially  by  heating  zinc 
oxide  with  silica  at  high  temperature. 

All  of  the  zinc  silicates  are  difficultly  fusible,  the  more  so  the  higher  their 
tenor  in  silica.  According  to  Percy  the  bisilicate  is  infusible  at  the  most 
.intense  white  heat,  while  the  singulo-  and  lower  silicates  melt  at  that 
temperature,  forming  more  or  less  translucent  slags  of  white-yellow  and 
green-yellow  color.  The  natural  silicate  smelts  at  the  same  temperature  to 
an  opaque,  stony  slag  of  grayish-green  color. 

The   properties   of   zinc   silicate   are   of   importance   in   the   practical 


CHEMISTRY    OF   THE   COMPOUNDS    OF    ZINC.  163 

metallurgy  of  zinc  inasmuch  as  willemite  and  hemimorphite  are  common 
ores,  while  losses  may  occur  through  the  formation  of  slag  in  the  retorts 
in  which  zinc  enters  as  silicate.  The  amount  of  zinc  absorbed  by  such  slags 
is  rarely  of  much  consequence,  however,  and  the  trouble  from  slags  in  zinc 
smelting  is  experienced  chiefly  from  the  other  elements  which  enter  into 
their  composition.  Zinc  silicate  is  reduced  by  carbon. 

ALUMINATE. — The  aluminate  of  zinc  (Al203,ZnO=Al204Zn)  occurs  in 
nature  as  the  mineral  gahnite.  It  may  be  produced  artificially,  as  colorless, 
octahedral  crystals,  which  are  harder  than  quartz,  by  fusing  a  mixture  of 
zinc  oxide,  alumina,  and  boric  acid.  Its  specific  gravity  is  4-58.  By  heating 
an  intimate  mixture  of  ZnO  and  Al20a,  in  the  proportion  of  1:6,  Percy 
obtained  a  sintered,  gray,  stony  mass,  which  scratched  flint  glass.  The 
aluminate  of  zinc  is  frequently  formed  in  the  walls  of  the  retorts,  which  are 
thereby  colored  a  deep  blue. 

FERRATE. — Ferrate  of  zinc  (ZnFe204=ZnO,Fe203)  occurs  as  black  and 
brilliant  octahedral  microscopic  crystals  in  an  analogous  manner  to  the 
aluminate.  Also  if  zinc  oxide  and  ferric  oxide  be  heated  to  redness,  and  the 
product  be  treated  with  insufficient  chlorhydric  acid  to  dissolve  all  the  iron, 
a  residue  is  obtained  which  contains  zinc  ferrate.  This  compound  is  one 
that  should  receive  more  study.  There  is  reason  to  believe  that  it  is  formed 
during  the  roasting  of  ferruginous  blendes,  and  if  that  be  so  it  is  probably  a 
matter  of  considerable  consequence  in  connection  with  hydrometallurgical 
processes  for  the  extraction  of  zioc. 

Zinc  ferrate  is  slightly  magnetic  and  has  a  specific  gravity  of  5-132. 
Apparently  it  is  reduced  by  carbon.  The  mineral  franklinite  is  a  complex 
mangano-ferrate  of  zinc,  iron  and  manganese. 

CHLORIDES. — Zinc  chloride  (ZnCl2),  also  known  as  zinc  butter  (French, 
beurre  de  zinc),  is  a  compound  of  zinc  which  is  used  extensively  in  the  arts 
and  is  the  soluble  form  into  which  the  zinc  in  ores  is  put  for  extraction  by 
certain  electrolytic  and  other  processes.  It  is  a  white,  deliquescent,  wax-like 
substance  of  sp.  gr.  2-75.  It  is  a  powerful  caustic,  being  distinguished  by 
its  property  of  burning  deeply  and  not  merely  superficially  like  many  others. 
A  concentrated  solution  of  zinc  chloride  converts  starch,  cellulose,  and  a 
great  many  other  organic  substances  into  soluble  compounds ;  hence  the  im- 
possibility of  filtering  a  strong  solution  of  zinc  chloride  through  paper. 

Zinc  chloride  is  formed  when  zinc  oxide  is  heated  to  redness  in  chlorine 
gas,  whereby  the  chlorine  combines  with  the  zinc  and  oxygen  is  liberated. 
Zinc  chloride  is  also  produced  by  the  combustion  of  zinc  in  chlorine,  wherein 
the  metal  burns  brilliantly;  by  the  action  of  chlorine  on  moist  zinc  at 
ordinary  temperatures ;  by  the  distillation  of  two  parts  of  mercuric  chloride 


164  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

and  one  part  of  zinc ;  by  the  distillation  of  a  mixture  of  anhydrous  sulphate 
of  zinc  and  sodium  or  calcium  chloride ;  or  from  one  part  zinc  oxide  and  two 
parts  ammonium  chloride;  or  by  evaporating  the  solution  of  zinc  oxide  in 
chlorhydric  acid  and  subliming  the  hydrous  chloride  (ZnCl2,H20)  thereby 
obtained;  or  by  the  addition  of  zinc  to  the  fused  chloride  of  an  electroneg- 
ative metal.  Sodium  chloride  added  to  a  solution  of  zinc  sulphate  gives 
zinc  chloride  and  sodium  sulphate,  which  may  be  separated  by  refrigeration. 

Zinc  chloride  melts  at  about  262°  C.  to  a  brownish  liquid,  which  boils  at 
708°-719°  C.,  and  volatilizes  without  decomposition  at  red  heat.  At  a 
high  temperature  it  is  decomposed  by  aluminum  with  the  formation  of  zinc 
and  aluminum  chloride.  It  is  soluble  in  absolute  alcohol  and  ether  and  is 
very  soluble  in  water.  The  aqueous  solution  is  .decomposed  by  the  electric 
current  with  the  liberation  of  zinc  at  the  cathode  and  chlorine  at  the  anode. 
Molten  zinc  chloride  is  also  decomposed  electrolytically  with  the  same 
results.  Numerous  processes  for  the  extraction  of  zinc  from  ores  have  been 
based  on  these  properties,  although  only  one  or  two  of  them  has  come  into 
practical  use. 

Zinc  chloride  has  a  remarkably  affinity  for  water,  so  much  so  that  it  is 
used  in  the  laboratory  as  an  absorbent  for  water  in  the  same  manner  as 
sulphuric  acid  is.  It  is,  indeed,  difficult  to  obtain  the  chloride  free  from 
water.  When  produced  by  crystallization  from  a  concentrated  solution  it  is 
obtained  as  ZnCl2+H20.  If  on  the  other  hand  the  solution  be  evaporated 
there  is  always  some  decomposition  into  basic  chlorides  and  hydroxide,  the 
following  reactions  taking  place  i1 

ZnCl2+H20=ZnO,HCl+HCl 
ZnO,HCl+H20=ZnO,H20+HCl. 

It  is  extremely  difficult  to  dehydrate  zinc  chloride,  without  driving  off 
chlorhydric  acid  and  forming  basic  chloride.  In  boiling  down  a  zinc  chlor- 
ide solution  and  fusing  the  salt  in  the. ordinary  manner  from  3  to  5%  of 
the  zinc  is  oxidized  and  the  equivalent  of  chlorhydric  acid  is  driven  oft', 
while  3  to  5%  of  water  always  remains  with  the  fused  chloride  even  at  high 
temperature;  evaporation  under  a  vacuum,  however,  is  said  to  remove  all 
the  water  besides  preventing  the  formation  of  basic  chloride.2 

Basic  chlorides,  or  oxychlorides,  of  zinc  are  also  formed  by  dissolving  zinc 
oxide  or  metallic  zinc  in  a  concentrated  solution  of  zinc  chloride ;  moreover 
in  diluting  an  aqueous  solution  of  zinc  chloride  to  a  certain  degree  there  is 
a  partial  decomposition  and  formation  of  oxy chloride.  When  zinc  hydrox- 

1  Remsen,  Inorganic  Chemistry,  p.  613.  t  Ashcroft,  loc.  cit. 


CHEMISTRY   OF   THE   COMPOUNDS   OF   ZINC.  165 

ide  is  precipitated  from  a  chloride  solution  by  means  of  milk  of  lime  or  milk 
of  magnesia,  some  oxychloride  goes  down  with  it.  In  the  chloridizing  roast- 
ing of  zinc  ore  with  salt  for  the  formation  of  zinc  chloride,  a  certain  pro- 
portion of  oxychloride,  which  is  non-volatile  at  the  sublimation  temperature 
of  the  simple  chloride,  is  formed.  These  oxy chlorides  are,  however,  volatile 
at  a  very  high  temperature,  say  1,200°  C.,  and  possibly  are  to  some  extent 
decomposed  into  zinc  oxide  and  chlorine.  Three  oxychlorides  of  zinc  have- 
been  definitely  described : 

(1)  ZnCl2,3ZnO :  dried  at  38°  C.  it  retains  four  molecules  of  water,  two 
of  which  it  loses  at  100°  C.    It  is  soluble  in  acids  and  alkalies,  but  only 
slightly  in  water. 

(2)  ZnCl2,6ZnO:  this  is  formed  by  the  action  of  water  on  the  am- 
moniacal  chlorides,  ZnCL>,2NH3  and  ZnCl2,4NH3 ;  it  is  precipitated  also  by 
adding  ammonia  to  a  solution  of  zinc  chloride  in  such  a  manner  as  to 
dissolve  a  part  of  the  precipitate.    At  ordinary  temperatures  it  holds  10H20, 
and  at  82°  C.,  6H20;  on  calcination  it  loses  water  and  some  zinc  chloride, 
and  becomes  a  more  basic  oxychloride.    It  is  insoluble  in  water. 

(3)  ZnCl2,9ZnO :  this  is  an  insoluble  white  powder  which  remains  when 
the  residue  from  the  evaporation  of  a  solution  of  zinc  chloride  to  sirup  con- 
sistency is  taken  up  with  water ;  it  is  also  produced  by  the  addition  of  enough 
potash  to  a  solution  of  zinc  chloride  to  give  an  alkaline  reaction;  in  the 
first  case  it  holds  back  3H20,  and  in  the  second  14H20. 

The  action  of  ammonium  chloride  upon  molten  zinc,  which  is  taken 
advantage  of  in  the  process  of  galvanizing  is  represented  by  the  equation : 

Zn+2NH4Cl=ZnCl2+2NH3-f2H 

The  zinc  chloride  formed  dissolves  oxide  from  the  surface  of  the  metal 
forming  zinc  oxychloride. 

Zinc  chloride  cannot  be  melted  safely  in  clay  or  earthenware  pots,  which 
being  porous  to  the  chloride  are  subject  to  disintegration  when  heated. 
When  free  from  lead  and  other  chlorides  and  also  from  water,  however,  zinc 
chloride  can  be  safely  fused  in  iron  pots  and  handled  with  iron  tools ;  which 
it  does  not  attack. 

There  are  several  ammoniacal  chlorides  of  zinc.  On  adding  ammonia  to  a 
concentrated,  warm  solution  of  zinc  chloride  until  the  precipitate  formed  is 
redissolved,  there  are  separated,  in  cooling,  crystals  of  the  composition 
ZnCl2,4NH3,H20.  Other  compounds  of  this  class  are  designated  ZnCl2, 
2NH  and 


166 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


Zinc  chloride  readily  forms  double  chlorides  analogous  to  those  formed  by 
magnesium  chloride.    The  following  combinations  have  been  identified : 


1.  ZnCl2,4XH4Cl 

2.  ZnCl2,3]XTH4Cl 

3.  ZnCl2,2NH4Cl+H20 

4.  ZnCl2,lXTH4Cl+2H20 


5.  ZnCl2,2KCl 

6.  ZnCl2,2NaCl+3H20 

7.  ZnCl2,MgCl2+6H20 

8.  ZnCl2,BaCl2+4H20 


The  substance,  ZnCl2,2NH4Cl-}-H20,,  is  formed  by  mixing  a  solution  of 
zinc  in  chlorhydric  acid  with  a  solution  of  ammonium  chloride.  It  is  used 
in  soldering,  serving  to  clean  the  surface  of  the  metal  by  the  action  of  the 
zinc  chloride  on  the  oxides. 

According  to  Kremers1  the  specific  gravity  of  solutions  of  simple  zinc 
chloride  (ZnCL)  varies  as  follows: 


Spec.  Grav. 

%ZnCl, 

Spec.  Grav. 

%  ZnCla 

1   1275 
1  '  2466 

13'8 
25-8 

1-3869 
1-5551 

37-5 
49'2 

BROMIDE. — Zinc  bromide  (ZnBr2)  is  produced  by  the  combustion  of  zinc 
in  bromine  vapor,  and  by  the  solution  of  zinc  oxide  in  bromhydric  acid.  On 
evaporating  this  solution  a  crystalline,  deliquescent  mixture  of  hydrous 
bromide  of  zinc  and  zinc  oxide  is  obtained  from  which  by  heating  strongly 
zinc  bromide  may  be  sublimed.  It  is  soluble  in  ether  and  alcohol  and  very 
soluble  in  water.  Pure  zinc  bromide  has  a  specific  gravity  of  3-643  at  10°  C. 
It  melts  at  394°  C.  and  boils  between  650°  and  700°. 

Ammoniacal  zinc  bromide  (ZnBr.>,2NH3)  crystallizes  out  of  a  solution  of 
zinc  bromide  in  warm  ammonia  water  on  cooling.  It  is  decomposed  by 
water  and  by  heat. 

IODIDES. — Zinc  iodide  (ZnI2)  is  produced  by  fusing  zinc  and  iodine,  or 
by  action  of  iodohydric  acid  on  zinc  or  zinc  oxide.  It  is  very  soluble  in 
water  and  on  calcination  is  decomposed  into  iodine  and  zinc  oxide.  Zinc 
iodide  has  a  specific  gravity  of  4-696.  It  melts  at  446°  C.  and  boils  at 
624°  C. 

The  ammoniacal  iodides,  double  iodides  and  oxyiodides  of  zinc  are 
analogous  to  the  bromine  and  chlorine  compounds.  The  following  have  been 
identified. 


•  Poggendorff  »  Annalen  der  Physik  und  Chemie  CV,  360. 


CHEMISTRY    OF    THE    COMPOUNDS    OF    ZINC.  167 

1.  ZnI2,5NH3,  formed  by  action  of  ammonia  gas  on  the  anhydrous 
iodide ;  decomposed  by  water. 

2.  ZnI2,4NH3 ;  decomposed  by  water. 

3.  ZnI2,2NH4I. 

4.  ZnI2,2KL 

5.  ZnI2,2NaI+3H20. 

6.  2ZnI2,BaI2. 

FLUORIDES. — Zinc  fluoride  (ZnFl2)  is  produced  by  precipitation  with 
potassium  fluoride  from  solutions  of  zinc  salts;  and  by  digestion  of  zinc 
oxide  with  fluorhydric  acid.  It  is  only  slightly  soluble  in  water,  more 
soluble  in  dilute  acids,  especially  in  fluorhydric,  and  very  soluble  in 
ammonia.  Its  specific  gravity  is  4-84  at  15°  C.  There  is  a  double  fluoride 
of  zinc  and  potassium,  ZnFl2,2KFl. 

HEAT  OF  FORMATION  OF  VARIOUS  COMPOUNDS  OF  ZINC.  . . 

The  heat  of  formation  of  various  compounds  of  zinc,  according  to  Thorn- 
sen's  thermochemical  investigations1  are  given  in  the  subjoined  tables.  All 
of  Thomson's  experiments  were  made  at  about  18°  C.  The  unit  of  heat 
referred  to  in  these  tables  is  the  quantity  required  to  raise  the  temperature 
of  one  gram  of  water  1°  C.  When  it  is  said  that  the  heat  of  formation  of 
any  compound  is  a  certain  number  of  units  it  is  meant  that  such  a  quantity 
of  heat  is  developed  in  the  production  of  a  quantity  of  the  substance  equal 
to  its  molecular  weight  in  grams ;  e.g.,  the  heat  of  formation  of  ZnO  from 
Zn  and  0  being  85,430  units  and  the  molecular  weight  of  ZnO  being 
654+ 16=81-4,  there  are  developed  85,430  gram  calories  in  the  production 
of  814  g.  of  zinc  oxide. 

Zn+O= ZnO 85.430  Gal. 

Zn+0-hH,O=ZnO,H,0 82,680    " 

Zn+2Br=ZnBr2 75,930 

Zn+2Cl  =  ZnCl2 97-210 

Zn-f-2I=ZnI2 49,230 

Zn-j-2O+SO2-f-7H,O=ZnSO4+7H2O 181,660 

Zn+2O-f  SO2  =  ZnSO4 158,990 

The  solution  of  the  zinc  salts  in  water  is  attended  by  development  of  heat 
or  the  reverse. 

ZnOl 2  dissolved  in  water  evolves 15,630  Cal. 

ZnSO4-KH2O        "          <«        "    absorbs 4.240    " 

ZnSO4  "        "    evolves.   18.500    " 

1  Thermochemische  Untersuchungen,  III,  275  et  seq. 


168 


PRODUCTION    AND   PROPERTIES    OF    ZINC. 


The  heat  of  formation  in  aqueous  solutions  is  given  in  the  following 
table: 

Zn+2Cl=ZnCl2 112,840  Cal. 

Zn-f  2H01=Zn012+2H 34,200 

Zn+O+SO3=ZnSO4 106,090 

ZnO+SO8=ZnSO4 20,660 

ZnO,H2O-f SO3=ZnSO4+H2O 23,410 

ZnO,H20+2H01=Zn012+H20 19,880 

ZnO,H,0==2C2H402=Zn(02H302)2+2H20 18,030 

Zn  f  2O+S02 =ZnSO4 167,470 

Zn-f-2Br=ZnBr2 90,960 

Zn+2I=ZnI2 60,540 

The  heat  of  formation  and  the  heat  of  decomposition  of  any  substance  are 
the  same ;  i.e.,  in  order  to  effect  the  decomposition  the  same  quantity  of  heat 
must  he  supplied  as  was  evolved  in  its  formation.  Thus  the  heat  of  forma- 
tion of  zinc  chloride  being  97,210  calories,  its  decomposition  requires  97,210 
calories. 


VIII. 

y 

THE  ORES  OF  ZINC. 

Zinc  ores  are  widely  distributed  throughout  the  world,  workable  deposits 
occurring  in  nearly  every  country  of  Europe  and  the  North  of  Africa, 
and  in  various  parts  of  the  United  States,  while  there  are  others  in  Aus- 
tralia, Canada  and  Mexico,  and  less  well  explored  regions,  which  are  not 
yet  available  to  a  very  large  extent  on  account  of  their  inaccessibility.  The 
principal  ores  of  zinc  are  the  sulphide,  the  carbonates,  the  silicates,  the 
compound  of  zinc  and  manganese  oxides  (franklinite)  and  the  simple  oxide 
(zinkite),  which  rank  in  importance  in  the  order  mentioned.  The  car- 
bonates and  silicates  are  commonly  referred  to  by  the  general  term  "cala- 
mine,"  which  was  formerly  the  only  class  of  zinc  ore  used  for  the  production 
of  spelter,  but  the  exhaustion  of  the  easily  worked  surface  deposits  brought 
the  undecomposed  sulphide  ore  into  the  market,  and  during  the  last  twenty 
years  its  importance  has  been  steadily  increasing.  At  the  present  time, 
however,  a  large  part  of  the  zinc  produced  in  Europe  is  still  derived  from 
calamine,  but  in  the  United  States  blende  is,  and  has  been  for  many 
years,  by  far  the  more  important  of  the  two  ores.  The  name 
"calamine"  is  used  here,  as  uniformly  throughout  this  treatise  to  indicate 
the  class  of  zinc  ores  comprising  both  the  carbonates  and  both  the  silicates, 
in  which  sense  it  is  commonly  employed  in  metallurgy,  although  this  does 
not  correspond  with  the  mineralogical  nomenclature  generally  accepted  in 
the  United  States.  A  different  custom  prevails,  however,  in  England,  and 
owing  to  the  consequent  uncertainty  that  must  necessarily  attend  the  use  of 
the  word  to  designate  a  single  mineral  species  it  seems  best  to  discard  it  I 
for  that  purpose.  This  was  discussed  by  me  in  a  paper  read  before  the 
American  Institute  of  Mining  Engineers  in  March,  1895,  as  follows: 

"The  hydrous  carbonate  is  known  mineralogically  as  hydrozinkite,  zinc- 
onise,  or  zinc-bloom ;  the  anhydrous  silicate  is  recognized  as  willemite. 
With  respect  to  the  anhydrous  carbonate  and  the  hydrous  silicate  there  is  a 
confusion  of  name  which  is  of  old  standing.  Attempts  to  clear  it  away 
were  long  ago  made  by  the  mineralogists  with  the,  result  that  there  is  now 

169 


170  PRODUCTION  AND.  PROPERTIES  OF  ZINC. 

a  more  or  less  national  uniformity  of  nomenclature;  but  there  is  still  an 
international  disagreement,  sometimes  very  perplexing  and  always  leading 
to  inexactness  in  expression. 

"The  name  calamine,  together  with  Galmei  of  the  Germans,  is  commonly 
supposed  to  be  derived  from  Kadjjieicf,  which  was  used  by  the  Greeks  to  desig- 
nate the  peculiar  kind  of  ore  employed  with  copper  in  their  brass-making, 
and  also  the  accretions  which  formed  in  the  brass-founder's  furnaces.  Agri- 
cola,  however,  says  that  it  is  from  calamus,  a  reed,  in  allusion  to  the  appear- 
ance of  the  material,  cadmia  fornacum,  which  collected  on  the  furnace 
walls.  But  whatever  the  derivation  of  the  word,  it  was  used  until  within 
100  years  to  include  all  the  oxidized  ores  and  compounds  of  zinc,  both 
natural  and  artificial.  Indeed,  the  difference  between  the  carbonates  and 
the  silicates  does  not  seem  to  have  been  suspected  before  1780,  when  Berg- 
mann  published  an  account  of  certain  experiments  upon  them;  and  it  was 
not  until  1803  that  their  true  composition  was  made  known  by  Smithson, 
and  all  doubts  as  to  their  being  distinct  mineral  species  were  cleared  away. 

"The  naming  of  these  minerals  is  described  by  Dana  in  his  System  of 
Mineralogy  (1892),  pp.  548-549.  In  1807,  Brongniart  called  the  silicate 
calamine,  leaving  for  the  other  mineral  its  chemical  name,  zinc  carbonate, 
by  which  it  continued  to  be  known  until,  in  1832,  Beudant  called  it  smith- 
sonite.  In  1852,  Brooke  and  Miller,  with  no  good  reason,  reversed  these 
names,  and  thus  led  to  the  confusion  which  still  exists.  On  account  of  this 
confusion,  Kenngott,  in  1853,  introduced  for  the  silicate  the  name  hemi- 
morphite,  which  has  not  been  generally  accepted. 

"At  the  present  time  American  usage  follows  Dana,  calling1  the  anhydrous 
carbonate  smithsonite  and  the  hydrous  silicate  calamine.  English  mineral- 
ogists, on  the  contrary,  generally  employ  calamine  to  designate  the  anhy- 
drous carbonate,  referring  to  the  hydrous  silicate  as  electric  calamine.  The 
application  of  the  name  smithsonite  to  the  hydrous  silicate  by  Brooke  and 
Miller  had  a  certain  following  in  their  time,  but  no  longer  obtains.  On 
the  Continent  of  Europe,  however,  the  equivalent  names,  calamine  and 
Galmei,  are  used  in  common  parlance,  especially  in  the  zinc  industry,  to 
include  the  four  mineral  varieties,  carbonates  and  silicates,  hydrous  and 
anhydrous.  In  Germany,  many  mineralogists  use  the  nomenclature  adopted 
by  Dana,  but  most  writers  on  technical  subjects  employ  Galmei  as  a  class 
name  only,  designating  the  silicate?  as  Kieselgalmet,  and  the  anhydrous 
carbonate  as  edler  Galmei.  Smithsonite.  or  ZinJcspath  (zincspar).  French 
writers  avoid  confusion  by  using  the  chemical  terms  zinc  carbonate  and  zinc 
silicate,  although  in  France,  a?  in  Germany,  calamine  (Galmei)  is  employe 
by  mineralogists  as  a  purely  scientific  name  for  a  distinct  species — tl 


THE   ORES   OF   ZINC.  171 

hydrous  silicate.  The  general  meaning  that  the  word  calamine  has  on  the 
Continent  is  undoubtedly  a  survival  of  the  custom  of  the  time  when  no 
difference  in  the  oxidized  ores  of  zinc  was  recognized,  together  with  the  fact 
that  metallurgically  they  belong  to  the  same  class." 

In  the  following  summary  of  the  properties  and  mineralogical  character- 
istics of  the  various  ores  of  zinc  Dana's  System  of  Mineralogy,  sixth  edition, 
has  been  drawn  upon  freely. 

BLENDE. — Zinc  sulphide,  ZnS  (also  known  as  sphalerite,  and  by  miners  as 
black  jack,  German  blende,  French  zinc  sulfure).  This  mineral  when  pure 
contains  Zn  67-15%  and  S  32-85%,  but  it  is  usually  contaminated  with 
iron,  manganese  or  cadmium,  and  rarely  by  mercury,  lead  and  tin;  traces 
of  indium,  gallium  and  thallium  are  found  in  blendes  from  certain  localities. 
Blende  is  often  argentiferous;  less  often  auriferous.  When  quite  pure, 
blende  is  white  or  nearly  colorless,  but  commonly  it  appears  yellow,  brown, 
black,  and  also  red  and  green,  owing  to  impurities.  Its  streak  is  usually 
brown,  but  may  be  light  yellow  and  white.  Pure  blende  is  transparent  to 
translucent,  but  the  ordinary  varieties  are  opaque.  It  crystallizes  in 
tetrahedral  forms  of  the  isometric  system,  but  the  crystals  are  frequently 
highly  complex  and  distorted.  Good  crystals  of  blende  are  rather  rare,  how- 
ever, and  it  is  found  commonly  in  crypto-crystalline  to  amorphous  forms, 
the  latter  sometimes  as  a  powder.  It  also  occurs  in  foliated  and  fibrous 
forms.  Its  fracture  is  conchoidal;  hardness,  3-5  to  4;  specific  gravity,  3-9 
to  4-1 ;  luster,  resinous  to  adamantine.  It  is  rather  brittle,  but  not  so  much 
so  as  galena. 

Blende  is  easily  identified  with  the  aid  of  the  blow-pipe.  In  the  open 
tube  it  gives  off  sulphurous  fumes.  In  the  reducing  flame  on  charcoal  it 
gives  a  coating  of  zinc  oxide,  which  is  yellow  while  hot  and  white  after 
cooling ;  if,  however,  the  mineral  contains  cadmium  a  reddish  brown  coating 
of  cadmium  oxide  will  be  formed  first.  Moistened  with  cobalt  nitrate  solu- 
tion the  zinc  coating  gives  a  green  color  when  heated  in  the  oxidizing  flame. 
Heated  with  soda  on  charcoal  in  the  reducing  flame  (after  a  preliminary 
roasting)  a  strong  green,  zinc  flame  is  emitted.  Blende  is  difficultly  fusible. 
It  dissolves  in  chlorhydric  acid  with  evolution  of  hydrogen  sulphide.  The 
mineral  with  which  it  is  most  likely  to  be  confused  is  galena,  which  certain 
of  the  lustrous  black  cryptocrystalline  varieties  resemble  strongly.  The 
characteristic  brown  streak  of  blende  and  the  black  streak  of  galena,  how- 
ever, form  an  easy  and  infallible  means  of  distinction. 

Several  varieties  of  blende  are  distinguished  according  to  the  presence  of 
other  sulphides,  isomorphous  with  the  zinc  sulphide. 

(a)     Ordinary,  containing  little  or  no  iron.     Its  color  is  usually  white  to 


172  rHODl'CTJON    AND    rHOPKKTIES    OF    Z1XC. 

yellowish  brown,  but  is  sometimes  black.  The  red,  or  reddish  brown,  trans- 
parent crystallized  kinds  are  sometimes  called  ruby  blende  or  ruby  zinc. 
Snow  white  blende  of  crystalline  form  has  been  found  at  Nordmark,  Sweden, 
and  at  Franklin  Furnace,  N.  J.  A  soft,  white,  amorphous  deposit,  forming 
a  powdery  mass  at  least  4  ft.  thick  and  30  ft.  in  length  was  once  found  at 
Galena,  Kan.1  Ordinary  blende  is  most  commonly  of  a  brownish  color  and 
resinous  appearance,  whence  it  is  frequently  referred  to  by  the  miners  as 
rosin- jack.  The  Joplin  blende  is  chiefly  of  this  variety. 

(b)  Marmatite,  ferriferous  blende,  containing  10%  or  more  of  iron, 
existing  as  moiiosulphide.     The  proportion  of  FeS  to  ZnS  ranges  as  high 
as  1 :2.     Ferriferous  blende  is  always  dark  brown  to  black  in  color.     Its 
luster  is  sometimes  dull;  sometimes  very  bright,  almost  metallic.     A  large 
part  of  the  blende  which  occurs  in  connection  with  galena  and  pyrite  in  the 
I'ocky  Mountains  is  of  this  variety.     The  percentage  of  iron  in  its  com- 
position is  very  variable,  as  to  which  the  intensity  of  the  black  coloration  is 
not  a  reliable  guide,  a  very  small  proportion  of  iron  sometimes  producing 
a  deep  black  color.     Ferriferous  blende  differs  from  the  ordinary  variety  in 
being  magnetic,  though  only  feebly  so ;  its  magnetic  susceptibility  increases 
with  the  percentage  of  iron  in  its  composition. 

(c)  Przibramite,  cadmiferous  blende  containing  up  to  5%  Cd  present  a-s 
sulphide.     Cadmiferous  blende  is  usually  reddish  in  color.   -  Although  cad- 
miferous blende  with  as  much  as  5%  Cd  has  been  described,  such  occurrence 
is  rare,  the  cadmium  tenor  of  commercial  blende  being  very  much  lower. 
Edmund  Jensch,  who  made  an  extremely  elaborate  investigation  of  this 
subject,  reported  that  of  the  ore  which  came  under  his  notice  the  kind 
richest  in  cadmium  was  a  lot  of  208  tons  of  black  blende  shipped  from  Abo, 
Finland,  in  1890,  which  contained  046%  Cd  and  3443%  Zn.2     Assuming 
that  the  cadmium  was  held  entirely  by  the  blende,  the  tenor  of  the  latter 
would  have  been  somewhat  under  \%  Cd. 

(d)  Wurtzitc,    a    ferriferous   blende    corresponding    to    the    formula, 
(>ZnS-}-FeS,  which  has  been  found  at  Oruro,  Bolivia,  and  at  Przibram, 
Bohemia.     It  occurs  as  hexagonal  crystals  of  3-9  to  4-1  sp.  gr.  and  3-5  to  4 
on  the  scale  of  hardness.     Its  color  is  brownish  black  and  streak  light 
brown.     This  variety  is  also  sometimes  cadmiferous. 

The  metallic  mineral  most  commonly  associated  with  blende  is  galena. 
The  deposition  of  both  these  minerals  seems  to  be  favored  by  limestone, 
in  connection  with  which  rock  the  most  important  deposits  are  found. 

"•  American  Journa'  of  Science,   1890,  XL,        DarsteUung  und  Verwendung,  In  Sammlung 
160.  Oiemischer  und  Chemisch-technischer  Vort- 

"  Das    Cadmium,    sein    Vorkommen,    seine        nige,  III.  vi,  201  to  232. 


THE    ORES    OF    ZINC.  173 

YoLTziTE.1 — This  is  an  oxysulphide  of  zinc,  corresponding  to  the  symbol, 
yjU0 -f-4;ZnS,  which  has  been  found  in  the  form  of  incrustations  at  Pontgi- 
hand,  France,  and  Joachimsthal,  Austria.  It  is  a  yellow  mineral  of  3-7 
sp.  gr.  and  4-5  on  the  scale  of  hardness. 

GOSLARITE. — Zinc  sulphate,  ZnS044-7H20,  containing  zinc  oxide  28-2%, 
sulphuric  anhydride  27-9%,  and  water  43-9%,  results  from  the  decompo- 
sition of  blende,  but  owing  to  its  easy  solubility  in  water  is  rather  rare  in 
occurrence.  It  is  a  brittle  mineral,  of  hardness  2  to  2-5,  sp.  g.  1-9  to  2*1, 
vitreous  luster  white,  reddish,  yellowish  and  bluish  in  color,  transparent  to 
translucent,  with  an  astringent,  metallic  and  nauseous  taste.  In  the  closed 
tube  it  yields  water  and  on  charcoal  gives  the  reactions  for  zinc,  besides 
forming  a  sulphide  which  when  moistened  tarnishes  silver. 

Ferrogoslarite,  in  which  part  of  the  zinc  sulphate  is  replaced  by  ferrous 
•sulphate,  occurs  in  some  of  the  mines  of  Missouri  and  Kansas,  where  it 
forms  mammillary  or  stalactitic  incrustations  of  a  light  yellow  to  brown 
color.  It  is  also  common  in  the  drainage  of  the  mines  of  that  region. 

SMITHSONITE. — Zinc  carbonate  ZnC03  (also  known  as  zinc  spar,  and  bj 
miners  as  dry  bone,  German  Galmei,  Edler  Galmei,  Kohlengalmei  or  Zink- 
spath,  French  zinc  carbonate).  This  mineral  when  pure  contains  carbonic 
dioxide  35-2%,  and  zinc  oxide  64-8%  (Zn,  62%).  However,  it  is  usually 
contaminated  by  iron,  manganese  or  cadmium  carbonates.  Pure  smithson- 
ite  is  a  brittle  mineral  of  hardness  5,  sp.  gr.  4-3  to  4-45,  uneven  to  imper- 
fectly conchoid al  fracture,  vitreous  luster,  inclining  to  pearly,  white  streak, 
and  color  white,  often  grayish,  greenish,  brownish  white  and  sometimes 
green,  bine  and  brown.  It  is  subtransparent  to  translucent.  It  crystallizes 
according  to  the  rhombohedral  system,  but  rarely  occurs  well  crystallized, 
being  found  rather  in  granular  and  earthy  forms. 

Several  varieties  of  smithsonite  are  distinguished  according  to  the  pres- 
ence of  foreign  elements,  catalogued  as  follows : 

(a)  Ordinary,  classified  as  (1)  crystallized,  (2)  botryoidal  and  stalac- 
titic, closely  resembling  similar  forms  of  hemimorphite  or  zinc  silicate,  (3.) 
granular  to  compact  masses,  and  (4)  earthy,  impure,  occurring  in  nodular 
and  cavernous  masses,  varying  from  grayish  white  to  dark  gray,  brown 
brownish  red  and  brownish  black  in  color,  and  often  with  drusy  surfaces  in 
the  cavities;  the  last  variety  is  the  "dry-bone"  of  American  miners,  which 
term  also  includes  some  hemimorphite. 

(b)  Monheimite  or  zinc-iron  spar,  ferriferous  smithsonite,  which  often 
contains  over  20%  of  iron  carbonate. 

I(c)     Maganiferous  smithsonite,  containing  5%  or  more  of  MnC03. 
1  This  spewing  *«  adopted  in  the  Century  Dictionary  instead  of  (he  cider  'cnn     voltxlne  ' 


174  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

(d)  Cadmiferous  smithsonite,  containing  up  to  5%  of  cadmium  car- 
bonate. In  Arkansas  and  Missouri  smithsonite  is  found  of  bright  orange 
yellow  color,  due  to  greenockite,  or  cadmium  sulphide;  this  is  known  locally 
as  "turkey  fat  ore/'  At  Wiesloch,  in  Baden,  a  yellow  variety  containing  as 
much  as  3%  Cd  used  to  be  found. 

These  varieties  are  not  often  well  denned,  usually  merging  into  one 
another  by  indefinite  gradations.  Thus  there  are  many  smithsonites  which 
are  both  ferriferous  and  cadmiferous.  The  Silesian  zinc  carbonate  ore  is 
notably  of  this  mixed  type.  As  in  the  case  of  blende,  the  percentage  of  cad- 
mium which  is  found  in  commercial  smithsonite  is  very  much  less  than 
would  be  inferred  from  the  statements  of  the  mineralogists.  In  an  investi- 
gation of  10  years  Jensch  failed  to  find  more  than  0-3%  Cd  in  any  Silesian 
ore,  while  the  average  of  all  his  analyses  was  only  about  (M%. 

Before  the  blowpipe  smithsonite  is  infusible,  but  when  moistened  with 
cobalt  nitrate  solution  and  heated  in  the  oxidizing  flame  on  charcoal  it  gives 
the  characteristic  reactions  for  zinc.  In  the  closed  tube  it  loses  its  carbonic 
anhydride.  It  is  soluble  in  chlorhydric  acid  with  effervescence,  which  reac- 
tion easily  distinguishes  it  from  all  other  zinc  ores  except  hydrozinkite.  The 
latter,  however,  gives  off  water  in  the  closed  tube,  which  smithsonite  does 
not  do. 

FRANKLINITE. — A  manganoferrate  of  iron,  manganese  and  zinc  [(Fe,Zn, 
Mn)0,  (Fe,Mn)203].  This  mineral,  which  is  found  in  large  quantities  at 
Stirling  Hill  and  Franklin  Furnace,  N".  J.,  and  is  of  rare  occurrence  else- 
where, contains  21%  Zn  when  it  corresponds  to  the  formula  here  given; 
its  composition  is  rather  irregular,  however,  the  relative  quantities  of  the 
different  metals  varying  rather  widely,  while  conforming  to  the  general 
formula  of  the  spinel  group.  It  is  a  brittle  mineral  of  conchoidal  to  uneven 
fracture,  hardness  5-5  to  6-5  and  sp.  gr.  5-07  to  5-22.  It  is  opaque,  with 
metallic  luster,  sometimes  dull,  and  iron-black  color.  It  is  slightly  mag- 
netic, which  property  enables  its  separation  from  the  willemite  and  zinkite, 
with  which  it  occurs,  by  the  powerful  effect  of  the  Wetherill  magnetic 
machines. 

It  is  easily  identified  by  its  reactions  before  the  blowpipe.  In  the  oxidiz- 
ing flame  with  borax  it  gives  a  reddish  amethystine  bead,  due  to  manganese, 
and  in  the  reducing  flame  this  becomes  bottle  green,  due  to  iron.  Fused 
with  soda  it  gives  a  bluish  green  manganate,  and  when  heated  on  charcoal  a 
faint  coating  of  zinc  oxide,  which  is  more  marked  when  a  mixture  with 
. borax  and  soda  is  used.  Franklinite  is  soluble  in  chlorhydric  acid.  It  is 
infusible  before  the  blowpipe.  Franklinite  crystallizes  in  the  isometric  sys- 


THE   ORES   OF   ZINC.  175 

tern,  affecting  the  octahedral  habit,  but  it  usually  occurs  massive,  granular, 
coarse  or  fine  to  compact. 

ZiNKiTE.1 — Zinc  oxide,  ZnO  (known  also  as  red  zinc  ore,  German  Roth- 
zinkerz,  French  zinc  oxyde).  Zinkite  when  pure  contains  80-25%  Zn  and 
19-75%  0.  Manganese  oxide  is  sometimes  present.  This  mineral  is  of 
rare  occurrence  except  at  Stirling  Hill  and  Franklin  Furnace,  N.  J.,  where 
it  is  found  in  considerable  quantity  in  connection  with  willemite  and  f rank- 
Unite.  It  is  a  brittle  mineral,  with  sub-conchoidal  fracture,  hardness  4  to 
4-5,  and  sp.  gr.  5-43  to  5-7.  It  is  translucent  to  sub-translucent,  has  a  Sub- 
adamantine  luster,  and  gives  an  orange  yellow  streak.  Its  color  is  deep  red, 
also  orange  yellow,  the  former  being  the  commoner.  In  crystallization  it 
affects  a  hemimorphic  form  of  the  hexagonal  system,  but  natural  crystals 
are  rare  and  it  usually  occurs  foliated,  massive,  or  granular. 

Before  the  blowpipe  it  is  infusible.  Heated  in  the  closed  tube  it  blackens, 
but  on  cooling  resumes  the  original  color.  On  charcoal  it  responds  to  the 
characteristic  tests  for  zinc.  It  is  soluble  in  chlorhydric,  nitric  and  sulphuric 
acids.  With  fluxes,  on  the  platinum  wire,  it  frequently  gives  a  reaction  for 
manganese,  because  of  contaminating  traces  of  that  element. 

HYDROZINKITE. — Zinc  hydrocarbonate,  3ZnOJC02-j-2H20  (also  known  as 
zinconise  and  zinc  bloom;  German,  Zinkbliithe).  Hydrozinkite  when  pure 
contains  11-1%  water,  13-6%  carbonic  dioxide  and  75-3%  zinc  oxide 
(57-1%  Zn).  It  is  an  earthy,  chalk-like  mineral,  which  usually  occurs, 
massive,  but  sometimes  as  incrustations,  which  may  be  reniform,  pisolitic,  or 
stalactitic.  Its  hardness  is  2  to  2-5,  sp.  gr.  3-J>8  to  3-8.  Its  luster  is  dull, 
streak  white  and  shining,  and  color  pure  white,  or  grayish  or  yellowish 
white.  With  the  blowpipe  hydrozinkite  gives  the  same  reactions  as  smith- 
sonite,  with  the  addition  that  in  the  closed  tube  it  yields  water,  by  which  it 
is  distinguished. 

Hydrozinkite  is  of  rather  rare  occurrence  as  an  ore,  except  in  the  prov- 
inces of  Santander  and  Guipuzcoa  in  Spain,  where  it  is  found  in  large  quan- 
tities. It  occurs  less  extensively  at  Bleiberg  and  Raibel  in  Carinthia.  In 
the  United  States  it  has  been  found  at  .Friedensville,  Penn.,  and  in  the 
Joplin  district  of  Missouri,  but  the  occurrences  are  only  of  mineralogical 
interest.  There  are  several  varieties  of  hydrozinkite,  which  are  classified 
mineralogically  as  follows: 

(a)  Ordinary,  as  described  above. 

(b)  Auricalcite,   or  "green   calamine,"   corresponding  to  the   symbol 
2ZnC03,3ZnH202,  in  which  a  part  of  the  zinc  is  replaced  by  copper. 

(c)  Buratite,  which  contains  both  copper  and  calcium. 

1  This  spelling  is  adopted  in  the  Century  Dictionary. 


176  PRODUCTION    AND    PROPERTIES    OE    ZINC. 

WILLEMITE. — Zinc  silicate,  2ZnO,Si02  (known  also  as  troostite).  Wille- 
mite  is  a  brittle  mineral  with  conchoidal  to  uneven  fracture,  hardness  5-5 
and  sp.  gr.  3-89  to  4-18.  It  is  transparent  to  opaque,  has  a  rather  weak 
vitreo-resinous  luster  and  white  or  greenish  yellow  color  when  purest ;  other- 
wise apple  green,  flesh  red,  grayish  white  or  yellowish  brown,  the  green  color 
being  most  characteristic.  When  impure  it  is  often  dark  brown.  Its  streak 
is  white  and  reddish.  The  crystals  of  flesh  red  or  gray  color,  opaque, 
found  in  New  Jersey  often  pass  under  the  name  of  troostite.  Willemite 
crystallizes  according  to  the  rhombohedral  system,  occurring  usually  in 
hexagonal  prisms.  It  also  occurs  massive  and  in  disseminated  grains. 

Before  the  blowpipe  willemite  fuses  with  difficulty  to  a  white  enamel. 
Heated  on  charcoal  it  gives  the  characteristic  reactions  for  zinc  which  are 
more  pronounced  when  the  mineral  is  mixed  with  soda.  It  is  decomposed 
by  chlorhydric  acid  with  separation  of  gelatinous  silica.  The  New  Jersey 
variety  phosphoresces  with  a  green  light  after  being  struck  with  a  hammer 
in  the  dark. 

Willemite  is  found  at  the  Vieille  Montagne  in  Moresnet,  but  the  only 
deposits  of  industrial  importance  are  at  Stirling  Hill  and  Franklin  Furnace, 
N".  J.,  where  the  mineral  occurs  intimately  mixed  with  franklinite  and 
zinkite. 

HEMIMORPHITE.1 — Zinc  hydrosilicate,  2ZnO,Si02-|-H20  (also  known  as 
electric  calamine  and  calamine;  German  Galmei,  Kieselgalmei  or  Kiesel- 
zinkerz;  French,  zinc  silicate).  Hemimorphite  contains  water  7-5%,  silica 
25%,  and  zinc  oxide  67-5%  (53-7%  Zn).  It  is  a  brittle  mineral  of  uneven 
to  subconchoidal  fracture,  hardness  4-5  to  5,  sp.  gr.  3-4  to  3-5.  It  is  trans- 
parent to  translucent,  has  a  vitreous  luster,  and  is  usually  white  in  color, 
sometimes  with  a  delicate  bluish  or  greenish  shade ;  also  yellowish  to  brown. 
It  crystallizes  in  the  orthorhombic  system,  affecting  hemimorphic  forms, 
whence  its  mineralogical  name.  It  also  occurs  massive  and  granular  and 
in  stalactitic,  mammillary,  botryoidal  and  fibrous  forms. 

Before  the  blowpipe  hemimorphite  is  almost  infusible.  In  the  closed  tube 
it  decrepitates,  whitens,  and  gives  off  water.  On  charcoal  it  gives  the  char- 
acteristic zinc  reactions.  It  gelatinizes  with  acid,  even  when  previously 
ignited,  and  is  soluble  in  a  strong  solution  of  caustic  potash. 

Clays  carrying  varying  amounts  of  zinc  silicate  are  common  in  Missouri 
and  Kansas  and  Virginia,  where  they  are  known  as  "joint  clays"  and  "tal- 

1  This  name  has  been  adopted  here,  con-  calamine  is  necessarily   used  in  its  metal 

trary  to  the  approved  mineralogical  nomen  lurgical  sense,   it  is  absolutely  essential 

clature  of  the  United  States,  because  in  a  have  a  distinct  designation  for  the  hydi 

treatise  of  this  character,  wherein  the  term  silicate  of  zinc  as  a  mineral. 


TI1K    DUES    OK    ZINC. 


177 


low  clays."  The  latter  are  very  fine  grained  and  plastic  and  on  drying  shrink 
and  crumble  into  small  fragments.  Their  tenor  in  zinc  oxide  varies  chiefly 
between  30  and  40^. 

ZINC. — Native  zinc  is  said  to  have  been  found  in  large  hexagonal  crystals 
of  the  rhombohedral  system,  exhibiting  a  perfect,  basal  cleavage,  in  a  geode 
in  basalt,  coated  with  smithsonite,  erythine  and  aragonite,  near  Melbourne, 
Australia ;  also  in  the  gold  sands  of  the  Mittamitta  Kiver.  It  is  described  as 
having  a  metallic  luster,  streak  and  color  bluish  white,  hardness  2,  and 
sp.  gr.  7.  There  is  some  doubt  as  to  the  authenticity  of  these  reported 
occurrences  of  native  zinc. 


IX. 
OCCURRENCE  OF  ZINC  ORE  IN  NORTH  AMERICA. 

Deposits  of  zinc  ore  are  widely  distributed  in  North  America,  but  many 
of  them  afford  mineral  of  undesirable  character  and  many  others  are  remote 
from  transportation  facilities,  on  which  accounts  the  workable  deposits  under 
existing  conditions  are  comparatively  few  in  number.  The  most  important 
of  them  are  situated  in  the  Joplin  district  of  Missouri  and  Kansas,  compris- 
ing the  southwestern  corner  of  the  former  State  and  the  southeastern  corner 
of  the  latter,  at  Stirling  Hill  and  Franklin  Furnace,  N.  J.,  in  the  vicinity 
of  Shullsburg,  Wis.,  and  the  vicinity  of  Pulaski,  Va.  Other  deposits  which 
have  been  exploited  in  the  past  and  may  be  reopened,  or  are  being  worked  on 
a  small  scale  are  situated  at  Friedensville,  Penn. ;  in  Wythe  County,  Va. ;  at 
Mossy  Creek,  Straight  Creek  and  Lead  Mine  Bend,  Tenn.,  and  in  Arkansas. 
In  Kentucky  there  are  deposits,  which  are  thought  to  have  some  promise, 
near  Marion,  in  Crittenden  County,  a  short  distance  south  of  the  Ohio 
River,  in  the  western  part  of  the  State;  production  therefrom  was  begun 
in  1901. 

Huge  deposits  of  mixed  ores,  containing  blende,  pyrite  and  galena  exist  in 
Colorado,  especially  at  Leadville  and  Kokomo,  and  numerous  attempts  have 
been  made  to  smelt,  or  treat  otherwise,  the  blende  separated  therefrom  by 
mechanical  (gravity  or  magnetic)  dressing;  lately  a  product  sufficiently  clean 
has  been  made  to  find  a  market  with  the  smelters  of  Europe  and  Kansas, 
while  a  better  grade  of  ore  has  been  produced  to  a  small  amount  at  Creede, 
Colo.  Deposits  of  zinc  ore  existing  at  Hanover,  N.  M.,  have  also  been 
worked  intermittently. 

The  Joplin  district  is  by  far  the  most  important  source  of  zine  ore  in 
North  America,  and  it,  together  with  the  New  Jersey  mines,  overshadows 
all  the  others.  Unfortunately,  there  are  no  statistics  of  the  production  of 
zinc  ore  in  the  United  States,  other  than  those  presented  in  Chapter  TV. 

The  geological  occurrence  and  the  date  of  earliest  exploitation  (in  a 
ous  way)  of  the  principal  zinc  ore  deposits  of  the  United  States  are  si 
marized  in  the  following  statement  in  tabular  form : 

178 


OCCURRENCE   OF    ZINC    ORE    IN    NORTH    AMERICA.  179 

ZINC    ORE    DEPOSITS    OF    THE    UNITED    STATES 


State 

Character  of 
Mineral 

Country 
Ro.k 

Geological 
Age 

Date  of  First 
Exploitation 

Arkansas  
Missouri-Kansas  . 
Nsw  Jers6y    ..... 

Calamine   and 
blende 
Calamine  and 
blende 
Franklinite 

Limestone 
Limestone 
Limestone 

Lower  Carbon- 
iferous 
Lower  Carbon- 
iferous 
Cam  brian 

1870 
1840 

New  Mexico 

and  willemite 
Calamine  and 

Limes  tone 

Lower  Carbon 

Pennsylvania  
Tennessee  

blende 
Calamine  and 
blende 
Calamine  and 

Limestone 
Limestone 

iferous 
Lower  Silurian 

1853 

Virginia  • 

blende 
Calamine 

Limestone 

Lower  Silurian 

1879 

"\Visconsin             . 

Calamine  and 

Limestone 

Lower  Silurian 

lotfU 

blende 

ARKANSAS. — Zinc  ore  has  been  discovered  at  numerous  points  in  this 
State,  but  few  of  the  deposits  have  yet  been  exploited  and  those  only  in  a 
desultory  manner,  owing  to  lack  of  transportation  facilities  heretofore.  The 
deposits  which  have  attracted  most  attention  are  situated  in  Marion,  Carroll, 
Boone,  Sharp  and  Lawrence  Counties  in  the  northern  part  of  the  State. 
They  are  described  as  irregularly  distributed  in  crevices  and  along  joint 
planes  in  magnesian  limestone,  the  crevices  frequently  enlarging  into  pockets 
or  cavernous  spaces  filled  with  ore,  clay  and  other  gangue.  At  some  points 
the  ore  has  impregnated  certain  strata  and  thus  occurs  at  a  definite  horizon. 
The  Rush  Creek  district  in  Marion  County  is  of  the  latter  character.  The 
principal  developments  in  Arkansas  have  been  made  in  that  district,  the  ore 
having  been  shipped  in  flatboats  down  the  White  River  to  Batesville,  a  dis- 
tance of  about  100  miles,  and  thence  by  the  Iron  Mountain  Railway  to  St. 
Louis  smelters.  The  production  up  to  the  present  time  has  been  intermit- 
tent and  small,  probably  not  to  exceed  1,000  tons  in  any  single  year,  but  in 
1901  renewed  attention  was  given  to  the  district  because  of  the  certainty 
of  its  being  speedily  opened  by  several  lines  of  railway  which  were  already 
building  into  it.  Some  of  these  lines  have  now  been  completed. 

The  zinc  region  of  Northern  Arkansas  lies,  generally  speaking,  to  the 
north  of  the  Boston  Mountains  and  west  of  the  St.  Louis,  Iron  Mountain  & 
Southern  Railway,  but  the  prospecting  for  and  the  development  of  the  ore 
deposits  has  not  yet  gone  far  enough  to  outline  more  than  vaguely  the  areas 
over  which  workable  deposits  exist  or  should  be  looked  for.  The  tardiness 
of  the  development  of  the  region  is  due  in  part  to  its  topography,  it  being 


180  PRODUCTION  AM)  PROPERTIES  OF  ZINC. 


a  hilly  and  partly  mountainous  country,  through  which  there  have  been  no 
railways  until  recently.  According  to  Doctor  John  C.  Branner,  now  of 
Stanford  University,  California,  and  formerly  State  Geologist  of  Arkansas, 
there  is  no  longer  any  doubt,  however,  about  the  existence  in  that  region  of 
large  bodies  of  zinc  ore.1 

Doctor  Branner  states  that  the  zinc  deposits  of  Northern  Arkansas  occur 
in  limestone  and  dolomite  of  Lower  Carboniferous  age.  The  occurrences  are 
classed  genetically  as  (I)  bedded  deposits  mostly  contemporaneous  with  the 
rocks  in  which  they  occur;  (II)  vein  deposits  of  older  age  than  the  inclosing 
rocks,  and  occurring  (a)  along  faults  or  fractures,  or  (&)  filling  brecciatcd 
beds  formed  along  underground  water  courses;  (III)  alteration  products, 
chiefly  carbonate  and  silicate  ores,  derived  by  alteration  from  the  sulphide 
ores  of  the  first  and  second  divisions.  Both  the  blende  and  the  calamine 
of  Northern  Arkansas  are  remarkable  for  their  purity.  Out  of  a  large 
number  of  analyses  of  the  blende  the  largest  quantity  of  iron  found  was 
0-67%.  Selected  samples  of  smithsonite  from  the  Morning  Star  mine 
showed  51-60%  Zn;  from  the  Legal  Tender  mine  49-91%.  The  early  zinc 
mines  of  Arkansas  were  opened  on  deposits  of  smithsonite  in  the  surface 
clays  and  soils,  along  and  near  the  outcrops  of  deposits  of  blende.  Although 
there  is  hardly  a  prospect  in  the  region  which  has  not  yielded  some  smith- 
sonite, there  is  but  little  search  nowadays  for  smithsonite  alone.  Doctor 
Branner  feels  reasonably  confident,  however,  that  when  the  search  for  zinc 
ore  in  Northern  Arkansas  has  been  properly  systematized  large  bodies  of 
smithsonite  will  be  discovered,  most  likely  in  regions  of  deep  rock  decay. 
Zinc  silicate  ore  is  much  less  abundant  in  Northern  Arkansas  than  either 
blende  or  smithsonite.  The  most  abundant  deposits  now  known  are  in  the 
Sugar  Orchard  district. 

Besides  in  Northern  Arkansas  there  appear  to  be  promising  resources  of 
zinc  ore  in  the  southern  part  of  the  State,  not  far  from  an  existing  line  of 
railway.  At  the  Petty  mine  of  the  North  American  Ore  and  Metal  Co.,  in 
Sevier  County,  about  70  miles  north  of  Texarkana  and  four  miles  from 
the  Indian  Territory,  there  is  a  shaft  175  ft.  deep,  with  several  levels  opened 
therefrom,  which  has  produced  about  700  tons  of  ore.  The  vein  is  a  fissure 
in  black  slate,  which  is  traversed  by  dikes  of  diorite.  The  ore  is  a  mixture 
of  blende,  chalcopyrite  and  argentiferous  galena.  Ordinary  jigging  has 
afforded  a  product  assaying  56%  Zn  and  ;>-5%  Fe,  but  with  the  aid  of 
magnetic  separators  a  concentrate  assaying  60%  Zn  and  1-81%  Fe  has  been 
produced  experimentally. 

1  In  a  paper  on  the  "Zinc  and  Lead  Deposits  of  North  Arkansas,"  read  before  the 
American    Institute    of   Mining   Engineers,    Nov.    1901. 


OCCURRENCE   OF    ZINC    OWE    IN    NORTH   AMERICA. 


181 


COLORADO.— The  immense  shoots  of  sulphide  ore  at  Leadville  have  large 
quantities  of  a  mixture  of  blende,  pyrites  and  galena  which  assays  about 
25%  Zn,  10%  Pb,  22%  Fe,  39%  S,  ±%  Si02  and  10  oz.  silver  per  2,000  11), 
In  1889  the  superintendents  of  four  mines  estimated  that  they  had  in  the 
aggregate  1,000,000  tons  of  such  ore  actually  blocked  out.  At  the  present 
time  the  quantity  opened  is  certainly  very  much  larger.  This  ore  was  early 
worked  to  a  considerable  extent  by  crushing  and  jigging,  by  which  process 
a  marketable  lead  ore  was  got  and  zinky  tailings,  high  in  iron  and  lead,  were 
thrown  away.  There  was  never  much  profit  from  the  operation.  Numer- 
ous attempts  were  made  to  work  the  zinky  tailings,  by  direct  smelting  for 
zinc,1  by  hydrometallurgical  methods,  and  by  careful  gravity  separation. 
The  last  method,  especially  by  employment  of  improved  shaking  tables 
(like  the  Wilfley,  Cammett,  Bartlett  and  others  of  that  type),  has  lately 
made  it  possible  to  obtain  a  clean  galena  and  pyrite  concentrate  and  a  by- 
product assaying  about  45%  Zn,  12%  Fe  and  6%  Pb,  which  has  found  a 
market  with  zinc  smelters,  and  although  fetching  only  a  low  price2  has 
made  the  operation  of  concentration  a  profitable  one.  In  1899,  1900  and 
1901  a  considerable  quantity  of  such  material  was  shipped  to  Mineral  Point, 
Wis.,  lola,  Kan.,  Antwerp,  Belgium,  and  Swansea,  Wales.  Recently  the 
separation  of  blende  from  Leadville  mixed  sulphide  ore  by  means  of  the 
Wetherill  magnetic  machines  has  been  undertaken  by  the  New  Jersey  Zinc 
Co.  at  Canon  City  and  the  Colorado  Zinc  Co.  at  Denver.  The  method 
employed  is  described  in  Chapter  XL  By  this  system  a  concentrate  assay- 
ing about  50%  Zn,  10%  Fe  and  1%  Pb  is  produced.  Some  analyses  of 
the  Leadville  mixed  sulphides  as  mined  are  given  in  the  subjoined  table. 

ANALYSES  OF  LEADVILLE  MIXED  SULPHIDE  ORES. 


Name  of  Mine. 

Zn. 

% 

Pb. 

% 

Fe. 

% 

S. 
% 

SiO, 
% 

Ag. 
oz. 

Col.  Sellers  
Mover 

24-50 
19*25 
24'00 

10-70 
16'  19 
IS'OO 

16-60 
624-60 
16*00 

40-00 
39-24 
40'00 

3-40 
0*96 

054-30 
7-50 
11*00 

Sierra  Nevada  

24'00 
32-40 

<J9'20 
<?4'30 

21-80 
20-60 

3-20 

c4'30 
4-20 

a  The  great  mass  of  this  ore  does  not  contain  more  than  10  oz.  Ag,  but  it  Is  not  un- 
common to  find  spots  where  the  silver  assay  is  as  high  as,  or  even  higher  than,  in  this 
analysis.  6  Includes  1-66%  Mn.  c  This  ore  also  contains  0-03  oz.  Au.  d  By  fire  assay. 
e  By  volumetric  analysis. 


Since  1899  considerable  zinc  ore  has  been  produced  by  mines  at  Creede, 
where  it  is  concentrated  to  a  product  assaying  55  to  59%  Zn,  3-75  to  6%  Pb 

'Denver  Zinc  Co.,  1887.  *  About  $6-50  per  ton,  f.  o.  b.  Leadville. 


182  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

and  1-1  to  2-1%  Fe,  which  has  been  shipped  to  smelters  in  Kansas.  The 
Creede  blende  generally  carries  2  or  3  oz.  Ag  per  ton  and  sometimes  is 
auriferous.  Blende  concentrates  have  also  been  produced  at  Montezuma, 
Summit  County,  and  at  Eico.  The  Eico  Mining  and  Milling  Co.  made 
shipments  to  Belgium  in  1901  of  zinc  concentrates  obtained  by  the  magnetic 
separation  of  ore  from  the  Atlantic  Cable  mine  at  Kico.  The  crude  ore, 
which  is  both  gold  and  silver  bearing,  is  said  to  assay  about  25%  Zn.  The 
magnetic  separating  mill,  which  has  a  capacity  of  60  tons  of  crude  ore  per 
day,  makes  a  zinc  concentrate  assaying  from  55  to  60%  Zn  and  less  than 
4%  Fe;  and  a  lead  concentrate  assaying  upward  of  60%  Pb  and  less  than 
3%  Zn.1 

Important  deposits  of  mixed  sulphides,  somewhat  similar  to  those  of 
Leadville,  exist  at  Kokomo,  Summit  County,  where  there  is  a  bedded  vein, 
10  to  12  ft.  thick,  of  great  extent.  In  this  there  are  shoots  of  high  grade 
silver-lead  ore,  but  the  great  mass  of  the  ore  is  very  low  in  lead,  or  destitute 
of  it,  being  essentially  a  mixture  of  blende  and  pyrite.  Its  composition  is 
approximately  20%  Zn  and  28%  Fe.  It  contains  4  or  5  oz.  Ag  and  0-2  to 
04  oz.  Au. 

KENTUCKY. — Zinc  ore  occurs  in  Kentucky  near  Marion  in  Crittenden 
County,  where  it  is  found  in  connection  with  the  deposits  of  fluorspar  and 
galena  which  have  been  worked  to  some  extent.  The  Columbia  mine  is 
said  to  disclose  a  fissure  vein  along  the  line  of  a  fault  of  which  the  dis- 
placement has  been  approximately  500  ft.  One  of  the  walls  is  limestone; 
the  other  a  sandstone  or  quartzite.  The  vein  varies  in  width  from  18  in. 
to  6  ft.  In  some  places  the  ore  spreads  out  laterally  as  "flats"  or  beds. 
The  ore  consists  of  galena  and  blende,  with  a  gangue  of  fluorite,  some  cal- 
cite,  a  little  clay,  and  small  quantities  of  barytes  and  quartz.  In  most  parts 
of  the  vein  only  the  ore  and  fluorite  are  met  with.  The  galena  occurs  in 
bunches  and  crystals  scattered  through  the  fluorspar  and  constitutes  about 
20%  of  the  entire  vein  material.  The  percentage  of  blende  appears  to  be 
rather  less  than  the  percentage  of  galena  so  far  as  the  vein  has  been  opened. 
The  mine  is  situated  about  four  miles  from  Marion.  Its  development  has 
not  been  extensive,  the  exploitation  having  been  done  in  a  desultory  man- 
ner, and  chiefly  for  galena  and  fluorspar  rather  than  for  zinc.  The  Old 
Jim  mine,  adjoining  the  Columbia,  produced  a  considerable  quantity  of 
calamine  from  surface  workings  in  1901. 

The  Tabb  mine,  south  of  Marion,  is  said  to  show  a  wide  vein,  standing 
vertically  and  of  great  longitudinal  extent,  of  which  one  wall  is  limestone 
and  the  other  a  sandstone  or  quartzite  of  undetermined  character.  The 

1  Eng.  and  Min.  Journ.,  Nov.  30,  1901,  p.  7S1. 


OCCURRENCE   OF   ZINC   OHE   IN   NORTH   AMERICA.  183 

mineral  is  a  resinous  blende,  low  in  iron,  which  is  very  finely  disseminated  in 
a  gangue  of  fluorspar.  The  ore  is  said  to  assay  25  to  35%  Zn.  Owing 
to  the  finely  disseminated  occurrence  of  the  mineral  and  the  difficulty  of 
separating  it  from  the  fluorspar  (sp.  gr.  3-1  to  3-2),  which  the  owners  of 
the  property  have  not  yet  been  able  to  accomplish,  no  mining  has  yet  been 
done,  except  a  small  amount  of  development  work.1 

MISSOURI  AND  KANSAS. — Zinc  ore  is  found  in  several  parts  of  Missouri, 
but  the  only  important  mines  are  those  of  the  Joplin  district,  by  which 
designation  is  understood  a  more  or  less  elliptical  area  comprising  the 
mines  of  Galena,  Kan.,  Webb  City,  Carterville  and  Joplin  in  Jasper 
County,  Mo.,  Granby  in  Newton  County  and  Aurora  in  Lawrence  County, 
besides  various  less  well  known  mining  centers.  Circumscribing  this  area 
by  an  ellipse,  its  long  axis,  extending  from  Aurora,  Mo.,  on  the  east  to 
Galena,  Kan.,  on  the  west,  a  distance  of  about  50  miles,  has  a  course 
a  little  north  of  west,  while  its  width  on  the  short  axis  extending  north 
from  Granby,  Mo.,  is  about  25  miles.  The  country  rock  of  the  region 
is  chiefly  limestone  of  the  Lower  Carboniferous  formation,  which  imme- 
diately underlies  the  adjacent  coal  measures  of  Kansas.  This  limestone  is 
not  everywhere  ore  bearing  throughout  the  district,  but  only  in  local  areas 
where  the  conditions  have  favored  the  deposition  of  mineral.  Surrounding 
such  areas  are  broad  tracts  of  barren  ground.  The  geographical  position 
of  the  zinc  bearing  areas,  together  with  the  location  of  the  coal  and  natural 
gas  fields  of  Kansas  and  the  principal  smelting  points,  is  shown  in  the 
accompanying  map,  of  which  the  scale  is  about  18  miles  to  the  inch. 

Nature  of  the  Ore  Deposits. — Broadly  considered  the  ore  deposits  are 
lenticular  masses  of  brecciated  and  mineralized  chert,  more  or  less  inter- 
mingled with  limestone  or  the  products  of  its  alteration  and  decomposition, 
and  surrounded  everywhere  by  limestone.  Many  of  these  lenses  are  of 
great  size,  especially  in  the  vicinity  of  Webb  City  and  Joplin,  Mo.,  and 
Galena,  Kan.,  where  stopes  occur  75  to  150  ft.  wide,  40  to  80  ft.  high,  and 
200  to  400  ft.  long,  from  which  all  the  material  extracted  has  been  milled.2 
The  smaller  lenses  are  15  to  50  ft.  wide,  5  to  30  ft.  high  and  100  to  500  ft. 
long.  In  one  instance  near  Joplin  a  channel  of  ore  was  followed  for  1,000 
ft.  These  lenses  and  channels  are  frequently  of  highly  irregular  shape, 
often  sending  out  sheets  and  pipes  into  the  surrounding  barren  country 
rock.  They  are  connected  with  a  system  of  fissures  in  the  country  rock 

1  The  Kentucky  zinc  deposits  occur  in  an       been  described  by  S.  F.  Emmons,  in  Trans, 
extension  of  the  lead  and  fluorspar  district       Am.   Inst.  Min.   Eng.,  XXI,  31. 
of  Rosiclare,  111.,  the  geology  of  which  has  -Walter  P.  Jenney,  ibid.,  XXII,  193. 


184 


OCCURRENCE    OF    ZINC    IN    NORTH    AMERICA.  185 

and  occasionally  the  latter  are  found  mineralized '  in  coincident  sheets. 
Thus,  Jenney  (loc.  cit.)  describes  vertical  fissures  in  the  district  which 
traverse  the  limestone  without  disturbing  the  stratification  or  producing 
any  brecciation  except  between  the  cheeks  of  the  fissures,  enclosing  veins 
of  mineral  after  the  usual  manner  of  "fissure  veins."  A  fissure  of  that 
character  near  Joplin  carried  ore  to  a  depth  of  60  ft.  with  a  longitudinal 
extent  of  200  ft.  and  thickness  of  4  to  12  ft.  between  walls. 

The  more  common  lenticular  masses  of  mineral  bearing  chert  in  general 
lie  nearly  horizontal.  As  would  be  naturally  expected,  the  distribution  of 
mineral  through  the  chert  is  irregular,  The  blende  occurs  impregnated  in 
seams  and  bunches  in  the  chert,  so  that  frequently  the  fragments  of  the 
latter  appear  cemented  together  by  the  blende,  which  everywhere  permeates 
the  mass  in  a  net-work.  As  the  ore  becomes  richer  the  seams  of  blende 
increase  in  thickness  and  sometimes  pockets  of  solid  blende  or  loose  aggre- 
gates of  crystals  (gravel  jack)  are  found.  Usually  the  proportion  of  blende 
increases  in  the  lower  part  of  the  deposit,  where  it  sometimes  entirely 
replaces  the  chert,  but  at  the  bottom  of  the  deposit  there  is  commonly  a 
layer  of  very  solid,  dense  chert,  which  cuts  off  the  zinc  ore.  It  is  often  the 
case,  however,  that  another  ore  body  comes  in  under  »uch  a  layer  of  chert, 
and  there  are  instances  where  four  successive  ore  bodies  have  been  opened, 
one  under  the  other,  with  intervening  partings  of  chert.  The  ore  bodies  are 
sometimes  identical  with  the  chert  lenses,  so  that  the  entire  lense  is  more 
or  less  impregnated  with  blende,  but  more  frequently  separate  ore  bodies 
occur  in  various  parts  of  the  larger  lenses. 

Grade  of  the  Ore. — It  will  be  inferred  from  the  foregoing  description 
that  the  grade  of  the  ore  of  the  Joplin  district  is  very  variable,  which  is  in 
fact  the  case,  the  run  of  the  ore  mined  ranging  from  an  insignificant  per- 
centage of  zinc  to  nearly  pure  blende.  Important  bodies  of  the  latter  char- 
acter are  rare,  however,  and  in  general  the  ore  raised  must  be  dressed.  With 
the  best  ores  one  ton  of  concentrate  assaying  60%  Zn  is  obtained  from  two 
to  five  tons  of  crude  ore,  while  the  poorer  ores  mined  yield  only  one  ton  out 
of  20  or  25  tons.  It  is  futile  to  attempt  to  reckon  the  tenor  .of  zinc  in  the 
crude  ore  from  the  above  statement,  since  there  are  extremely  variable, 
but  generally  high,  losses  in  dressing  according  to  the  Joplin  practice. 
This  subject  is  discussed  at  more  length  in  Chapter  XI,  q.  v.  J.  E.  Holi- 
baugh,  in  The  Mineral  Industry,  II,  670,  stated  that  some  ore  bodies  would 
yield  75%  to  80%  mineral,  while  in  others  the  average  would  not  be  over 
10%.  In  The  Mineral  Industry,  III,  537,  he  stated  that  at  that  time  (1894) 
few  mines  could  be  worked  at  a  profit  which  did  not  yield  10%  of  mineral, 
the  average  value  of  blende  in  that  year  having  been  $17-10  per  2,000  Ib. 


186 


c 

pq 
pq 


~ 
O 


OCCURRENCE    OF    ZINC    ORE    IN    NORTH    AMERICA. 


187 


at  the  mines,  though  a  large  deposit  of  ore  yielding  1%  had  been  worked 
profitably  in  the  Victor  mine  at  Carterville,  a  large  tonnage  being  handled 
daily.  At  the  present  time  the  average  yield  of  the  district  is  probably  not 
more  than  5%  and  many  mines  that  yield  only  4%  are  being  worked.1 

Deposits  of  smithsonite  and  hemimorphite,  classed  together  as  "silicate 
ore"  by  the  miners  of  the  district,  occur  especially  in  the  vicinities  of 
Aurora  and  Granby,  where  ore  of  that  character  is  got  rich  enough  to  ship 


Flint  rodk 


Subcarboniferous  limestone, 

SU*          -jBfr 

&+,  ^Zinc-blende  ore-bodies 
+  3  f  and  Flint  rock 


Workedoul  part  of 
ore-deposit 

Qalenitein  fissures  <snd  bedding  planesjn  limestone 

FIG.  11.  —  VERTICAL  SECTION  OF  A  TYPICAL  ORE  DEPOSIT  NEAR  WEBB 

CITY,  Mo.2 

in  lump  form.  As  sent  to  the  smelters  it  probably  averages  40  to  45%  Zn. 
Elsewhere  in  the  Joplin  district  blende  is  the  predominant  mineral.  Ga- 
lena is  commonly  associated  with  it,  but  it  has  been  found  that  the  latter 
mineral  more  frequently  occurs  in  the  formations  near  the  surface,  while  in 
the  lower  parts  of  the  ore  bodies  there  is  less  of  it,  and  often  none  at  all. 


1  There  is  no  doubt  that  the  average  yield 
per  ton  of  crude  ore  mined  and  milled  in 
the  Joplin  district  has  greatly  diminished 
during  the  last  10  years. 


'These  illustrations  are  reproduced  from 
the  paper  on  "Zinc  Blende  Mines  and  Mining 
near  Webb  City,  Mo.,"  by  Carl  Henrlch,  In 
Trans.  Am.  Inst.  Min.  Eng.,  XXI,  3. 


188 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


Where  the  two  minerals  occur  together  there  is  no  sharp  line  of  demarka- 
tion,  but  in  dressing  there  is  no  difficulty  in  separating  the  two  minerals 
when  intermingled.  As  the  surface  deposits  are  exhausted  the  proportion 
of  lead  ore  to  zinc  ore  won  is  decreasing.1  Fortunately,  there  is  not  as  a 
rule  a  large  percentage  of  pyrite  associated  with  the  blende  of  the  Joplin 
district,  but  there  are  some  mines  where  it  runs  so  high  as  to  prevent  the 
production  of  a  marketable  ore  by  ordinary  gravity  concentration. 

Other  accessory  minerals  are  marcasite  and  chalcopyrite  and  bitumen, 
but  these  arc  rare  and  of  no  important  effect  upon  the  character  of  the  zinc 
ore.  Mention  should  be  made,  however,  of  the  masses  of  clay,  generally  of 
red  color,  but  sometimes  yellow,  brown  or  black,  which  occur  in  cavities  in 
the  brecciated  deposits,  which  are  of  particular  interest  because  of  their 
high  tenor  in  zinc  silicate.  A  series  of  thirteen  analyses  of  this  material, 
reported  by  Winslow,2  shows  a  range  from  2-36%  to  56-12%  ZnO.  These 
clays  are  abundant  in  some  places,  but  the  variability  of  their  tenor  in 
zinc  and  the  difficulty  of  separating  the  low  grade  from  the  high  grade 
has  hitherto  prevented  their  utilization. 

The  Missouri  blende  is  commonly  of  the  brown,  resinous  character,  often 
ruby  red,  sometimes  black  and  rarely  white.  Mineralogically,  it  is  very 
pure,  containing  only  insignificant  proportions  of  isormorphous  iron  and 
cadmium.  The  following  analyses,  although  of  old  date,  convey  an  idea 
of  the  purity,  of  the  mineral : 


Locality. 

Zinc. 

Iron. 

Cadmium. 

Silica. 

Joplin  
Joplin  
Granby..  .  . 

65-92% 
64-87 
64-67 

0-32% 
0  37 
0-53 

0  509% 
0'723 

0  25% 
1  41 
2-05 

The  concentrated  ore  produced  at  the  present  time  averages  about  60% 
zinc.  Its  tenor  in  lead  may  be  put  down  at  0-5  to  1%,  and  in  iron 
from  1  to  2%.  It  assays  about  30%  S,  and  the  remainder  of  its  composi- 
tion, besides  a  little  cadmium,  is  silica,  It  is  free  from  both  arsenic  and 
selenium. 

Mining  Conditions. — The  operating  of  mines  on  leased  land  is  almost  a 
universal  practice  in  the  district.  Under  this  system  the  fee-owner  usually 


1  The  production  of  lead  ore  and  zinc  ore 
during  the  last  seven  years  was  as  follows 
the  zinc  ore  being  stated  In  brackets  :  1 895 
31,294  (144,487)  ;  1896,  26.927  (153,082) 
1897,  29,578  (177,975)  ;  1898,  26.457  (235. 
323)  ;  1899,  24.100  (256.456)  :  1900.  28.500 
(242.500)  :  1901,  35.000  (258.000).  Ac- 


cording to  these  figures  the  ratios  are :  1895. 
1  :4-6;  1896,  1  :5-7 ;  1897.  1  :6 ;  1898,  1  :9 : 
1899,  1  :10-6;  1900,  1:8-5;  1901,  1  :7-4.  The 
Joplin  lead  ore,  as  concentrated,  assays 
about  77%  Pb  on  the  average,  the  best 
grades  having  a  tenor  of  about  80%  Pb. 
2  Missouri  Geological  Survey.  VTI.  li.  445. 


OCCURRENCE    Or    Z1XC    ORE    IN    NORTH    AMERICA. 


189 


<rives  a  lease  on  a  large  tract  of  his  land  at  a  royalty  of  from  8  to  15%  of 
the  gross  output  of  mineral,  the  lease  being  made  usually  for  a  period  of 
10  years.  The  lessee  prospects  the  tract  by  drilling  or  sinking  shafts,  and 
if  mineral  is  found,  sub-leases  portions  of  the  property,  usually  lots  of  200 
ft.  square,  at  a  royalty  of  15  to  25%  of  the  gross  output  of  mineral.  In 
.<ome  cases  the  fee-owner  operates  his  own  mines  and  frequently  a  lessee 
prefers  to  work  a  rich  deposit  rather  than  to  sub-lease  it.  This  system  has 
at  least  one  good  result,  inasmuch  as  it  makes  the  district  largely  free  from 
labor  difficulties,  so  many  miners  being  directly  interested  in  the  opera- 
tions. Experience  has  shown  also  that  in  the  long  run  the  system  is  prob- 
ably the  most  economical  under  the  existing  conditions,  since  although  a 


FIG.  12. — PLAN  OF  ORE  DEPOSIT  SHOWN  IN  FIG.  11. 

Limits  of  ore  or  flint  body  are.  aaa  at  level  A,  Fig.  11 ;  6&6  at  B;  ccc  at  C;  and  ddd  at  D. 

The  dotted  line  incloses  the  area  within  which  there  is  no  adequate 

support  of  the  root"  of  the  ore  deposit. 

company  operating  its  own  property  on  a  large  scale  can  mine  and  mill 
most  cheaply,  lessees  are  at  an  advantage  in  exploring  for  new  ore  bodies. 
Mining  is  done  in  the  Joplin  district  from  the  grass-roots  down  to  250  ft, 
the  average  depth  of  all  the  shafts  operated  being  probably  about  120  ft. 
Many  drill-holes  have  recently  been  put  down  to  depths  of  250  or  300  ft. 


190  PRODUCTION  AND  PROPERTIES  OF  ZINC, 

and  rich  ore  has  been  struck  at  greater  depths.  The  contract  price  of  churn- 
drilling  to  ordinary  depths  is  $1-25  per  ft.,  but  better  figures  can  be  obtained 
on  large  contracts.  Owing  -to  the  shattered  condition  of  the  rock  formation 
and  the  presence  of  chert  in  irregular  and  broken  masses,,  the  diamond  drill 
has  not  been  successful  in  the  Joplin  district.  The  cost  of  shaft-sinking  is 
very  variable,  depending  on  the  locality  or  kind  of  ground.  According  to 
Harold  A.  Titcomb,1  a  6X7  ft.  shaft  was  sunk  80  ft.  on  contract  in  the 
Belleville  district  for  $2  per  ft.;  this  shaft  was  in  soft  open  ground.  A 
5X7  ft.  shaft,  70  ft.  deep,  two  miles  west  of  Joplin,  cost  $20-25  per  ft., 
that  figure  including  a  small  boiler  and  pump.  A  shaft  125  ft.  deep  was 
sunk  one  mile  west  from  Joplin  at  a  cost  of  $14-30  per  ft.;  90  ft.  was  in 
hard  flint  and  limestone  and  35  ft.  in  open  ground. 

The  cost  of  mining  and  milling  in  the  Joplin  district  is  discussed  in 
Chapter  XI. 

Literature. — There  is  an  extensive  literature  concerning  the  geology  of 
the  Joplin  district,  its  ore  bodies  and  their  origin.  The  most  recent  works 
are  a  paper  by  Carl  Henrich  on  "Zinc  Blende  Mines  and  Mining  near  Webb 
City,  Mo.,"  Trans.  Am.  Inst.  Nin.  Eng.,  XXI,  3  to  25 ;  by  Walter  P.  Jenney, 
on  "The  Lead  and  Zinc  Deposits  of  the  Mississippi  Valley,"  ibid.,  XXII, 
171  to  225;  by  Arthur  Winslow,  on  "The  Lead  and  Zinc  Deposits  of  Mis- 
souri," ibid.,  XXIV,  634  to  689 :  and  vols.  VI  and  VII  of  the  report  of  the 
Missouri  Geological  Survey,  by  Arthur  Winslow,  published  in  1894;  also 
"The  Galena-Joplin  Lead  District,"  by  E.  Haworth,  in  The  Mineral  Indus- 
try, vol.  Vlll. 

NEW  JERSEY. — The  great  zinc  mines  of  this  State  are  situated  in  the 
towns  of  Ogdensburgh  and  Franklin  Furnace,  at  Stirling  and  Mine  hills 
respectively,  in  the  valley  of  the  Walkill  Eiver,  a  small  stream,  about  12  to 
15  miles  south  of  the  New  York  state  line  and  40  miles  in  a  direct  line  and 
60  miles  by  railway  from  New  York  city.  They  were  owned  by  General 
Lord  Stirling  and  worked  by  him  for  iron  previous  to  the  Revolution,  and 
about  1840  were  first  worked  for  zinc,  though  for  the  next  10  or  15  years 
the  various  enterprises  were  more  or  less  unsuccessful.  The  zinc  mines 
of  this  district  have  had  an  eventful  history,  and  were  involved  in  what 
appeared  to  be  an  endless  litigation  until  in  1895  the  conflicting  interests 
were  consolidated  in  a  new  corporation,  known  as  the  New  Jersey  Zinc  Co. 
That  company  now  controls  all  the  mines  in  Sussex  County,  N.  J.,  and  in 
the  Saucon  Valley,  Penn. 

Geology  of  the  Ore  Deposits. — Both  at  Stirling  Hill  and  Mine  Hill,  the 
former  being  two  miles,  south  20°  west,  from  the  latter,  the  ore  bodies  occur 

iEng.  and  Min.  Journ.,  July  28,  1900. 


OCCURRENCE   OF   ZINC    ORE   IN   NORTH   AMERICA. 


191 


as  beds  lying  between  strata  of  white  limestone  of  Cambrian,  Cambro- 
Silurian,  or  Archaean  age,  which  have  been  contorted  in  a  remarkable  man- 
ner. The  Stirling  Hill  bed,  or  vein,  as  it  is  commonly  referred  to,  strikes 
southwest  for  1,100  ft.,  then  curves  around  for  300  ft.  and  strikes  north- 
east, parallel  with  its  own  extension,  for  about  475  ft.,  until  it  ends.  Both 
parts  of  the  vein  dip  about  60°  east. 

The  vein  at  Mine  Hill  presents  analogous,  but  even  more  complicated  fea- 
tures. It  strikes  south  30°  west  for  about  2,500  ft.,  then  bends  around 
in  a  sharp  fold  and  strikes  to  the  east  at  an  angle  of  about  30°  with  its 
other  extension,  and  after  running  approximately  600  ft.  pitches  below  the 
surface  at  an  angle  of  27°  or  28°,  though  it  has  been  proved  by  borings  and 


MAP 

OF 

JRANK.LINITE  DEPOSIT 

FRANKLIN  FURNACE^  N.J. 

Scale  8oo'«=i" 


FIG.  13. 

a  shaft  to  extend  about  2,000  ft.  further,  where  its  depth  below  the  surface 
is  about  1,000  ft.  In  the  western  vein  the  ore  dips  southeastward  at  angles 
varying  between  37°  and  60°  ;  in  the  eastern  vein  it  is  nearly  vertical. 

The  outcrop  of  the  Stirling  Hill  vein  plotted  on  the  map  resembles  a 
hook  in  its  shape.  That  of  the  Mine  Hill  vein  resembles  a  wire  bent 
sharply  in  two  legs  at  an  angle  of  30°,  one  leg  being  short  but  of  equal 
length  to  the  other  if  its  known  extension  underground  be  plotted.  In 
transverse  sections  both  deposits  show  as  two  veins  dipping  more  or  less  in 
the  same  direction  and  one  apparently  underlying  the  other,  wherefore  they 
are  frequently  referred  to  as  the  "front"  and  "back"  veins. 

The  Stirling  Hill  veins  vary  from  4  to  20  ft.  in  thickness,  throughout 
which  the  zinc  minerals  are  disseminated,  but  not  uniformly.  In  the  front 
vein  the  portion  near  the  foot  wall  shows  a  band  richer  in  zinkite  and  willem- 


192 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


ite  than  that  near  the  hanging,  but  it  is  hardly  enough  to  justify  speaking 
of  two  veins,  a  zinkite  vein  and  a  franklinite  vein,  as  has  been  done.1  Both 
are  irregular  and  pinch  because  of  the  coming  in  of  the  foot  wall.  The  ore 
body  is  an  impregnation  of  the  limestone  along  this  horizon  with  the  ore 
bearing  minerals  in  a  greater  or  less  degree  and  with  a  streak  richer  in 
zinc  next  the  hanging.  As  much  as  20  ft.  in  thickness  has  been  taken  out 
tip  to  the  limits  where  the  walls  became  too  lean  to  work. 

The  Mine  Hill  vein  is  as  much  as  50  ft.  thick  in  places  and  even  more 
at  the  bend.  Frank  L.  Nason,  in  a  paper  in  Trans.  Am.  Inst.  Min.  Eng.f 
February,  1894,  which  goes  extensively  into  the  geology  of  the  deposit,  con- 
siders that  the  ore  body  is  equivalent  to  a  prism  3,500  ft.  long,  800  ft.  wide 


Weights  and  Measures 


Back  Vein 


layior  Mine  Opening 

i 

Tunnel  through  Pillar 

^Hddle  Level 

l 


IL 

>Lowe»  Lorel  Drift 

i    I 


V  V    v "~V  V    vxv     *«£  »• 

Vv^W'^X^ 
VyV'     <%&$> 

FIG.  14. — TRANSVERSE  SECTION  OF  ZINC  ORE  DEPOSIT  AT  FRANKLIN 

FURNACE,  K  J. 

Section  A  on  Pig.   13.     Scale,   1   inch=200  feet. 

and  25  ft.  thick.     It  is  probably  the  largest  single  deposit  of  zinc  ore  ever 
found  in  the  United  States  and  one  of  the  largest  known  in  the  world. 

Character  of  the  Ore. — The  zinc  ore  of  New  Jersey  is  essentially  a  mix- 
ture of  zinkite,  willemite  and  franklinite,  forming  a  rock-like  mass  (accord- 
ing to  F.  L.  Clerc,  whom  I  quote  because  of  the  aptness  of  his  description) 
not  unlike  in  appearance  an  eruption  of  granite,  in  which  the  franklinite 
represents  the  quartz,  the  willemite  the  feldspar  and  the  zinkite  the  mica. 
The  analogy  would  be  more  exact  if  the  ore  were  compared  to  a  garneti- 
ferous  syenite,  in  which  the  greenish  orthoclase  might  stand  for  the  wille- 
mite, black  hornblende  for  the  franklinite  and  the  red  garnet  for  the 


1  J.  P.  Kemp.  The  Ore  Deposits  at  Frank- 
lin Furnace  and  Ogdensburgh,  N.  J..  in 
Trans.  New  York  Academy  of  Science,  XIII. 
76  to  08.  Reference  should  be  made  to  this 


paper  for  a  more  complete  knowledge  of  the 
highly  interesting  geology  of  these  New  Jer- 
sey mines. 


OCCURRENCE    OF    /IXC    OJ5K    IX    XO11TJ1    AMERICA. 


193 


zinkite,  but  neither  any  granite  nor  the  imaginary  syenite  would  have  the 
distinctly  crystalline  appearance  and  brilliancy  of  the  New  Jersey  zinc  ore. 
Besides  the  franklinite,  willemite  and  calcite  there  are  small  quantities  of 
zinkite,  tephroite,  garnet,  and  occasionally  other  minerals.  The  mineral- 
ogical  composition  of  the  ore  is  approximately  as  follows:  franklinite, 
51-92%  ;  willemite,  31-58%  ;  calcite,  12-67%  ;  zinkite,  0-52%  ;  tephroite  and 
other  silicates,  3-31%;  total,  100%.  Its  chemical  composition  is  ZnO, 
29-35%  (Zn,  23-58%;  0,  5-77%) ;  Fe20a,  32-06% ;  MnO,  11-06% ;  CaCO,, 
12-67%;  Si02,  etc.,  14-57%;  total,  99-71%.  Owing  to  the  low  tenor  in 
zinc  and  the  high  percentages  of  iron  and  manganese,  the  ore  was  not  used 
extensively  for  the  manufacture  of  spelter  until  recently,  but  was  employed 


v  v  v  v  vv 
vv  v  v 

V  » V   .. "    v  v'     "    "^    Y      v     V        v 

vv  „  v  ^  v  v       vv      vv 
v    v    v      vv 

FIG.  15. — TRANSVERSE  SECTION  OF  ZINC  ORE  DEPOSIT  AT  FRANKLIN 

FURNACE,  N.  J. 

Section   B   on   Fig.   13.     Scale,   1   inch=200  feet. 

chiefly  for  making  zinc  white.  The  development  of  special  processes  of 
mechanical  separation  of  the  minerals,  which  are  described  in  Chapter  XI, 
has  made  the  ore  a  source  of  high  grade,  remarkably  pure  zinc  mineral. 

Exploitation  of  the  Mines. — At  the  time  of  the  visit  of  the  American 
Institute  of  Mining  Engineers  to  Franklin  Furnace,  N.  J.,  Feb.  24,  1899, 
it  was  stated  that  the  great  ore  body  at  that  place  (Mine  Hill)  was  then 
known  to  be  over  3,500  ft.  long  and  in  places  over  200  ft.  thick.  At  the 
south  end  of  the  outcrop  the  ore  was  to  be  worked  by  an  open  cut,  and 
there  the  overlying  limestone  was  being  removed.  The  ore  then  mined 
came  from  a  shaft  950  ft.  deep,  sunk  in  the  hanging  wall.  The  ore  body 
had  been  opened  by  a  number  of  drifts  and  raises,  but  there  were  no  stopes, 
nor  had  any  definite  system  of  mining  been  laid  out,  as  the  shape  of  the  ore 


194  PRODUCTION  AND  PROPERTIES  OP  ZINC. 

body  in  the  deep  levels  was  still  undetermined.  Considerable  surface  wat<  r 
gets  into  the  mine  through  fissures  in  the  limestone,  one  large  stream  having 
been  cut  at  586  ft.  in  sinking  the  shaft.  All  the  water  collecting  at  the 
bottom  is  sent  to  surface  in  one  lift  by  a  duplex,  triple-expansion  Worth - 
ington  steam  pump,  which  has  a  capacity  of  nearly  1,000  gals,  per  minute. 
The  output  of  the  mine  in  February,  1899,  was  about  400  tons  of  ore  daily, 
but  before  the  completion  of  the  new  mill  then  under  construction  there 
was  expected  to  be  a  productive  capacity  for  1,000  tons  per  diem. 

Operations  at  Stirling  Hill  have  now  (1901)  been  discontinued,  it  having 
been  found  that  the  ore  of  the  mine  there,  although  abundant,  is  leaner 
than  that  of  Mine  Hill  and  that  greater  economy  can  be  secured  for  the 
present  by  confining  work  to  the  latter  deposit.  In  1900  the  New  Jersey 
Zinc  Co.  produced  and  sent  to  its  mills  198,262  long  tons  of  ore,  all  of 
which,  save  1859  tons,  came  from  Mine  Hill.  There  were  shipped  37,622 
tons  of  crude  ore,  and  concentrated  160,640  tons,  the  latter  yielding  148,917 
tons  of  mineral,  or  nearly  93%  of  the  weight  of  the  ore  as  received  from 
the  mines.  This  remarkable  showing  of  richness  was  made  from  ore  of 
which  the  bulk  was  derived  from  development  work  in  the  deep  levels  of  the 
mine.  According  to  the  New  Jersey  Geological  Survey,  the  total  produc- 
tion of  these  mines,  which  are  the  only  ones  in  that  State,  was  191,220  long 
tons  in  1901  against  194,881  in  1900. 

NEW  MEXICO. — Deposits  of  zinc  ore  near  Hanover  in  the  southwestern 
part  of  this  Territory  have  been  exploited  to  a  small  extent.  They  occur  in 
gray  and  white  limestone  of  Lower  Carboniferous  age,  or  older.  The  de- 
posits are  of  two  classes,  calamine  and  blende,  and  according  to  W.  P. 
Blake,1  are  rather  unique  in  some  respects.  Apparently  the  deposits  of 
calamine  and  blende  have  no  direct  connection.  The  former  have  been 
quarried  out  from  the  surface  downward  in  irregular  pits  and  cave-like 
excavations,  in  some  cases  to  a  depth  of  60  ft.  or  more,  gradually  thinning 
out  to  mere  seams.  The  ore  is  chiefly  smithsonite,  often  in  close  association 
with  aggregations  of  small  crystals  of  quartz.  The  best  ore  as  shipped 
assays  35  to  38%  Zn.  Blende  also  occurs  in  masses  in  the  limestone,  but 
although  they  may  be  oxidized  superficially,  these  deposits  have  no  coi 
nection  with  those  previously  described.  The  blende  is  of  the  dark,  reddis 
brown  variety,  free  from  arsenic  and  antimony,  but  commonly  intermingh 
with  pyrites ;  galena  is  entirely  absent. 

The  masses  of  blende  ore  generally  occur  at  the  contact  of  the  limestoi 
with  dikes  of  igneous  rocks,  from  which  the  ore  is  separated  by  a  sheet  of 
hard,  tough  rock,  known  locally  as  "green  rock."  which  consists  of  fibrous 

i  Trans.  Am.  Inst.  Min.   Eng.   XXIV,  187. 


OCCURRENCE    OF    ZINC    OKE    IX    XOIJTJ1    AMKUICA.  195 

amphibole,  together  with  garnet  and  probably  epidote,  and  in  places  carries 
hematite,  with  blende  and  pyrite  more  or  less  intermingled.  The  form  of 
the  deposits  of  blende  is  generally  lenticular,  but  being  mostly,  if  not  in  all 
cases,  along  the  planes  of  contact  of  intrusive  dikes,  or  following  the  plane 
of  faults,  they  have  such  linear  extension  and  sequence  as  to  present  the 
general  appearance  of  lodes.  Actinolite  and  garnet  occur  with  the  mineral 
elsewhere  than  near  the  dikes  and  Blake  considers  them  to  be  of  contem- 
poraneous origin  with  the  ore.  The  garnet  is  of  a  wax-yellow  color,  the 
variety  grossularite,  and  somewhat  resembles  resinous  blende  in  its  appear- 
ance. Owing  to  the  nearness  of  its  specific  gravity  to  that  of  blende  it  is 
with  difficulty  separated  from  the  latter  by  gravity  concentration. 

Shipments  of  zinc  ore  are  made  from  the  Hanover  district  to  North  Chi- 
cago, 111.,  and  Mineral  Point,  Wis.,  but  the  high  cost  of  transportation 
thither  has  heretofore  prevented  any  extensive  exploitation  of  the  mines. 

PENNSYLVANIA. — Zinc  ore  has  been  mined  at  several  places  in  this  State, 
especially  at  Friedensville,  Lehigh  County;  in  Sinking  Valley,  near  Bir- 
mingham in  Blair  County;  near  Landisville  in  Lancaster  County;  on  the 
Susquehanna  River  a  few  miles  below  Sunbury  in  Northumberland  County, 
and  on  Pickering  Creek  a  few  miles  south  of  Phenixville  in  Chester 
County.  Of  these  the  Friedensville  deposits  were  the  most  important  and 
are  of  interest  now,  since  they  are  likely  to  be  reopened. 

Friedensville. — The  Friedensville  mines  are  situated  in  the  Saucon  Val- 
ley, a  few  miles  south  of  Bethlehem.  According  to  H.  S.  Drinker,1  zinc  ore 
was  first  discovered  there  in  1845,  and  mining  on  an  extensive  scale  was 
begun  in  1853  by  the  Pennsylvania  &  Lehigh  Zinc  Co.,  which  at  the  same 
time  erected  smelting  furnaces  and  a  zinc  oxide  plant  at  Bethlehem.2 
Three  mines,  known  as  the  TTeberoth,  Hartman  and  Saucon  were  opened; 
they  are  situated  within  half  a  mile  of  each  other.  The  ore  occurs  in  a 
stratum  of  magnesian  limestone  of  Lower  Silurian  age,  which  strikes  north- 
east and  southwest. 

The  character  of  the  deposits  has  been  somewhat  differently  described  by 
Henry  D.  Rogers,3  Frederick  Prime,4  F.  L.  Clerc,5  and  H.  S.  Drinker.8  A 
comparison  of  their  accounts  indicates  that  there  are  three  channels  of  ore, 
on  which  the  three  mines  named  were  respectively  opened,  formed  by 
replacement  of  a  part  of  the  limestone,  or  of  parallel  strata  of  it,  with 
connecting  cross-seams.  In  each  mine  the  ore  shoot  pitches  to  the  south- 

1  Trans.  Am.  Inst.  Min.  Eng.,  I,  67.  4  Report  of  the  Second  Geological  Survey 

2  J.   D.  Whitney,  Metallic  Wealth   of  the       of  Pennsylvania.  D3,  vol.  I. 

United  States,  edition  of  1854.  p.  351.  •  Mineral  Resources  of  the  United  States, 

8  Geology   of  Pennsylvania,   two  volumes,        1882,  p.  361. 
published  in  1868.  •  Loc.  cit. 


196  PRODUCTION    AND   PROPERTIES    OF    ZINC. 

west.  In  the  Ueberoth  mine  the  limestone  strata  are  much  disturbed  and 
stand  nearly  vertical ;  in  the  Hartman  mine,  distant  about  half  a  mile  from 
the  Ueberoth,  the  strata  are  less  disturbed  and  the  dip  is  less  steep;  in  the 
Saucon  mine,  distant  two  furlongs  from  the  Hartmann,  the  regularity  of 
the  strata  is  still  more  pronounced  and  their  dip  more  gentle. 

In  the  Ueberoth  mine  there  were  six  parallel  seams  of  ore  interlammated 
with  limestone  strata  and  connected  by  six  perpendicular  seams.  At  the 
intersections  there  were  found  enlargements  of  the  ore  body,  some  of  these 
bulges  being  20  ft.  thick  and  60  ft.  wide.  These  seams  were  followed  for 
more  than  1,000  ft.  on  their  strike  to  a  depth  of  225  ft.  vertically,  or  250  ft. 
on  the  dip,  at  which  depth  the  operation  of  the  mine  was  discontinued  with 
no  signs  of  failure.  In  the  Hartmann  and  Saucon  mines  the  ore  shoots 
were  more  compact  and  lenticular  in  form.  That  of  the  Saucon  mine  was 
remarkably  regular  in  pitch,  course  and  width.  It  pitched  to  the  south  at 
an  angle  of  about  30°,  was  60  ft.  in  width  and  had  a  thickness  of  30  ft. 
The  Hartmann  mine  was  worked  to  a  depth  of  150  ft.  The  Saucon  ore 
shoot  was  followed  250  ft.  by  the  Bergenpoint  Zinc  Co.,  gaining  a  vertical 
depth  of  110  ft.,  and  was  followed  150  ft.  further  by  the  Lehigh  Zinc  Co., 
into  whose  property  it  had  passed,  a  total  depth  of  200  ft.  being  reached. 

The  Ueberoth  mine  was  worked  continuously  from  1853  to  the  autumn 
of  1876,  when  it  was  closed  on  account  of  the  great  quantity  of  water  which 
had  to  be  pumped.  Even  at  the  depth  of  40  ft.  there  was  a  great  flow  of 
water;  at  150  ft.  depth  the  then  famous  pump,  known  as  the  "President," 
was  installed.  This  was  a  Cornish  pump,  with  a  110  in.  single  cylinder, 
double  acting,  condensing,  walking-beam  engine,  10  ft!  stroke,  designed  to 
work  four  30-in.  plunger  pumps  and  four  30-in.  lift  pumps,  with  10  ft. 
stroke,  and  to  take  water  from  a  depth  of  300  ft.  When  work  was  stoppt 
it  was  running  six  to  seven  strokes  per  minute,  and  operating  three  paii 
of  30-in.  pumps  and  one  pair  of  22-in.  and  was  easily  handling  the  wal 
that  came  to  them. 

The  Hartmann  and  Saucon  mines  were  wet,  but  the  flow  of  water 
them  was  less  than  in  the  Ueberoth,  and  they  continued  to  be  operated  foi 
some  time  after  the  Ueberoth  was  closed.     They  were  being  worked  on 
small  scale  in  1882.     Up  to  the  end  of  1876  the  Ueberoth  mine  is  said 
have  produced  about  300,000  tons  of  ore,  of  which  one  third  came  from 
great  body  opened  close  to  the  surface. 

Character  of  the  Ore. — The  ore  of  the  Saucon  Valley  was  calamim 
(smithsonite  and  hemimorphite)  near  the  surface,  changing  to  blende  witl 
depth.  The  oxidation  was  deepest  in  the  Ueberoth  mine  and  least  in  the 
Saucon.  The  blende  is  of  the  cryptocrystalline  variety,  with  a  conchoida] 


OCCURRENCE   OF    ZINC    ORE   IN    NORTH   AMERICA. 


197 


fracture  and  bluish  slate  color.  It  is  remarkably  free  from  lead,  arsenic 
and  antimony,  wherefore  a  high  grade  of  spelter  was  made  from  it,  but  it  is 
somewhat  mixed  with  pyrite,  which,  together  with  its  cryptocrystalline 
character,  makes  it  difficult  to  concentrate.  According  to  Clerc  (loc.  cit.) 
it  assayed  from  35  to  40%  Zn  as  sent  to  the  works,  and  since  he  describes 
it  as  resembling  broken  limestone,  I  infer  those  figures  represent  a  cobbed 
and  sorted  product. 

TENNESSEE. — Zinc  ore  has  been  mined  at  several  places  in  upper  East 
Tennessee,  where  deposits  of  the  mineral  have  been  found  in  nearly  every 


Phila.  &  Readiug  Ry. 
to  Phila. 


FIG.  16. — MAP  OF  NORTHAMPTON,  LEHIGH  AND  CARBON  COUNTIES, 

PENNSYLVANIA. 
(SCALE  1  IN.  =  24  MILES.) 

Showing  location  of  zinc  mines  and  smelteries  and  the  eastern  extension  of  the  anthracite  coal  field. 

county  of  the  region,  though  but  few  of  them  appear  to  be  of  any  economic 
importance.  The  most  work  has  been  done  at  Mossy  Creek,  New  Market, 
Straight  Creek  and  Lead  Mine  Bend.  In  1900  a  deposit  of  carbonate  ore 
was  opened  near  Mascot  on  the  line  of  the  Southern  Eailway,  and  an  oc- 
currence of  blende  was  exploited  near  McMillin  Station,  in  Knox  County. 
There  are  two  forms  of  deposits  of  zinc  ore  in  Tennessee. 

Mossy  Creek  and  New  Market. — One  type  occurs  in  the  so-called  Knox 
dolomite,  which  is  of  Lower  Silurian  age,  at  Mossy  Creek,  on  the  main  line 
of  the  Southern  Railway  from  Knoxville  to  Asheville,  the  zinc  bearing 
strata  extending  in  a  southwestward  direction  from  Mossy  Creek  through 


I 


198  PRODUCTION   AND   PROPERTIES    OF   ZINC. 

New  Market  to  within  six  miles  from  Knoxville.     Masses  of  smithsoni 
were  found  originally  in  this  area,  lying  on  a  jagged  surface  of  limesto 
and  surrounded  by,  or  covered  by,  a  bed  of  red  clay.    The  ore  was  of  gr 
purity,  like  that  of  the  Virginia  deposits,  which  are  not  a  great  distan 
away,  and  in  some  respects  its  occurrence  was  similar,  although  where  e 
ploited  the  overlying  bed  of  clay  was  not  so  deep  nor  has  the  corrod 
surface  of  the  limestone  the  pinnacle  structure  of  the  Bertha  mines.    C 
mine  deposits  of  this  character  were  worked  at  Mossy  Creek  by  the  Ed 
Mixter  &  Heald  Zinc  Co.  and  the  Bertha  Zinc  and  Mineral  Co.,  and  at  N 
Market  by  the  Ingalls  Zinc  Co. 

Immediately  under  the  surface  deposits  of  carbonate  ore  the  limesto: 
carries  blende  of  a  light  brown  color,  occurring  as  thin  veinlets  or  seams 
ramifying  in  all  directions.  The  limestone  is  greatly  broken  up.  Th 
seams  of  ore  are  rarely  half  an  inch  wide  and  seldom  more  than  a  few  f 
in  length.  They  appear  to  have  been  deposited  in  joint  planes  and  irregular 
fractures  in  the  country  rock.  The  mineral  is  distributed  in  this  manne 
through  a  thick  stratum  of  limestone;  in  the  course  of  a  brief  examinatio: 
in  November,  1899,  I  was  unable  to  discover  any  systems  of  enrichmen 
which  might  be  followed  in  mining  the  ore,  nor  did  the  miners  who  had 
worked  there  know  of  any.  Apparently,  the  only  practical  method  of 
mining  was  to  break  out  all  the  rock  and  sort  that  in  which  the  mineral 
was  most  thickly  disseminated.  Ore  could  be  so  sorted  as  to  assay  8%  Zn 
The  blende  is  commonly  accompanied  by  barite,  which  makes  it  difficult  to 
produce  a  concentrate  assaying  more  than  50%  Zn. 

The  above  description  applies  particularly  to  Mossy  Creek.  At  New 
Market  the  occurrence  is  similar,  but  the  ore  bearing  stratum  of  limestone 
is  said  to  be  only  50  ft.  wide,  which  is  less  than  at  Mossy  Creek.  The  fol- 
lowing analyses  of  ore  from  New  Market  were  made  at  the  University  o: 
Tennessee:  smithsonite— ZnC03,  83-29%;  Si02,  13-10%;  FeC03,  1-32%; 
Fe203,  0-66%;  CaC03,  1-07%;  MgC03,  0-56%;  blende— ZnS,  84-75%; 
Si02,  7-57%;  Fe20,+Al203,  1-66%;  CaC03,  5-98%;  MgC03,  0-04%. 

The  mines  at  Mossy  Creek  formerly  owned  by  the  Edes,  Mixter  &  Heald 
Zinc  Co.  have  been  more  recently  exploited  by  the  John  Weir  Lead  &  Zinc 
Co. ;  those  at  New  Market  are  idle ;  other  deposits  in  the  district  are  worked 
in  a  desultory  manner  by  individuals,  who  sell  the  ore  to  the  Bertha  Zinc  & 
Mineral  Co.  or  to  smelters  in  Indiana. 

Straight  Creek. — A  mine  was  also  worked  by  the  Edes,  Mixter  &  Heald 
Zinc  Co.  and  later  by  the  John  Weir  Lead  &  Zinc  Co.  at  Straight  Creek  in 
Claiborne  County,  about  three  miles  west  of  Lone  Mountain  Station,  on 
the  Knoxville  &  Cumberland  "Railway.  At  this  place  there  is  a  limestone 


OCCURRENCE    OF    ZINC    ORE    IN    NORTH    AMERICA. 


199 


formation  striking  north  70°  east,  and  dipping  south  20°  east  at  a  slope  of 
35°  at  the  point  where  the  ore  outcropped;  in  going  east  the  dip  increases 
to  60°.  A  shoot  of  ore  pitching  east  and  partly  replacing  a  stratum  of  the 
limestone  outcropped  on  the  side  of  a  hill  and  has  been  followed  several 
hundred  feet,  changing  from  calamine  to  blende  with  depth.  The  ore 
bulges  and  pinches  in  lenticular  form,  sometimes  attaining  a  width  of  20  ft. 
and  a  height  of  30  ft.,  but  is  generally  of  less  dimensions.  Near  the  ore 
body  caverns  of  irregular  shape  are  frequently  found  in  the  limestone. 
The  carbonate  ore  has  been  entirely  mined  out  of  this  shoot.  The  sulphide 
ore  body  consists  of  small  streaks  or  lenticles  of  blende  interlaminated  with 


V  I  R  G  I  N  LA 
7VSST"? 


7,'<\  JOHNSON  J 
X  • 


^ 


FIG.  17. — MAP  OF  EASTERN  TENNESSEE. 

Showing  location  of  zinc  mines. 

limestone.  After  breaking  it  can  be  readily  separated  as  lump  ore  assaying 
40%  Zn.  The  blende  is  of  the  grayish  brown,  cryptocrystalline  variety. 
It  is  quite  free  from  pyrites,  but  some  galena  is  intermixed  with  it. 

Lead  Mine  Bend. — About  16  miles  west  of  the  Straight  Creek  mine, 
within  a  quarter  of  a  mile  of  the  Powell  Eiver,  is  the  Lead  Mine  Bend 
property,  which  occurs  in  a  similar  limestone  formation,  but  the  beds  there 
lie  more  flatly.  This  mine  was  originally  worked  for  lead,  as  its  name 
implies,  and  has  been  extensively  developed.  The  mineral  occurs  in  a 
channel  made  up  of  bunches  and  lenticles  of  galena  and  blende  interlami- 
nated with  limestone  and  following  a  crevice  which  breaks  longitudinally 


200  PRODUCTION    AND    PROPEKTIKS    OF    ZINC. 

an  anticlinal  fold  in  the  limestone.  The  axis  of  the  anticline  dips  8°  east. 
The  crevice,  which  is  nearly  vertical,  shows  a  nearly  continuous  streak  of 
ore  for  a  longitudinal  distance  of  several  hundred  feet  and  a  depth  of  40  ft. ; 
perhaps  more.  The  ore  extends  out  into  the  limestone  50  to  100  ft.  on  each 
Bide  of  the  crevice,  and  the  strata  appear  to  be  mineralized  for  about  20  ft. 
perpendicularly  to  their  dip.  The  mineralization  is  irregular,  however, 
and  generally  a  large  proportion  of  barren  rock  must  be  broken  to  get  the 
ore.  The  latter  can  be  hand-sorted  up  to  about  40%  Zn.  The  blende  is 
grayish  brown  and  cryptocrystalline,  free  from  pyrites,  but  intermixed  with 
galena. 

Mining  Conditions. — Both  the  Straight  Creek  and  Lead  mines  belonged 
to  the  Edes,  Mixter  &  Heald  Zinc  Co.,  which  closed  them  down  in  1893, 
owing  to  inability  to  operate  them  profitably  under  the  then  existing  con- 
ditions. The  ore  of  the  Lead  mine,  which  was  the  most  productive,  has 
to  be  carted  20  miles  over  a  rough  road,  or  floated  down  the  Powell  and 
Clinch  rivers  in  flatboats  to  Clinton,  for  which  there  is  enough  water  only 
during  a  short  period  of  the  year.  The  ore  was  formerly  smelted  at 
Clinton,  where  the  Edes,  Mixter  &  Heald  Zinc  Co.  had  a  small  plant,  which 
is  now  in  ruins.  Since  it  was  dismantled  such  ore  as  has  been  produced 
in  Tennessee  has  been  shipped  to  smelters  in  Indiana  and  to  the  Bertha 
works  at  Pulaski,  Va.,  the  latter  receiving  only  calamine.  Save  for  the 
lack  of  transportation  facilities  the  Tennessee  mines  are  favorably  situated, 
the  costs  of  labor  and  fuel  being  low  in  the  districts  where  they  are. 

UTAH. — This  State,  like  several  of  the  other  mining  states  of  the  Rocky 
Mountains,  possesses  extensive  resources  of  zinc  ore,  chiefly  of  a  mixed  char- 
acter, which  have  not  yet  been  developed  to  any  important  degree.  The 
Horn  Silver  mine,  at  Frisco,  is  said  to  have  300,000  tons  of  ore  blocked  out, 
which  will  average  5  to  8%  Pb,  3  to  7%  Fe,  and  about  35%  Zn  (the  range 
in  zinc  being  from  25  to  40%) ;  it  is  said  to  contain  about  0-06  oz.  Au  and 
7  oz.  Ag.  The  gangue  is  silicious.  The  great  pyrites  deposits  of  Bingham 
Canon  contain  considerable  blende  in  some  portions.  A  good  deal  of  blende 
occurs  in  the  ore  raised  from  the  mines  at  Park  City.  As  compared  with 
Colorado,  Utah  is  at  a  disadvantage  with  respect  to  the  markets  for  zinc  ore, 
which  is  likely  to  retard  the  development  of  its  resources,  because  of  the 
higher  cost  of  transportation. 

VIRGINIA. — The  zinc  mines  of  this  State  are  situated  in  the  southeast 
corner  of  Wythe  County,  in  the  "Valley  of  Virginia,"  so-called.  Three 
mines  have  been  worked  there,  namely,  those  of  the  Bertha  Zinc  &  Mineral 
Co.,  those  of  Manning  &  Squier  adjoining  the  Bertha  on  the  northeast,  and 
those  of  the  Wythe  Lead  &  Zinc  Co.  at  Austinville,  eight  miles  to  the 


OCCURRENCE    OF    ZINC    ORE    IN    NORTH    AMERICA.  201 

southwest.  Other  mines  have  been  opened  at  Ivanhoe,  a  little  beyond 
Austinville.  These  mines  are  included  within  an  area  10  miles  long  in  a 
direct  line  bearing  north  55°  east,  on  the  south  side  of  New  River,  which 
flows  northeastward  in  a  tortuous  course.  The  greatest  distance  of  any  of 
the  mines  from  the  river  is  a  little  less  than  two  miles.  The  most  impor- 
tant mines  are  those  of  the  Bertha  company.  They  were  discovered  in  1866, 
but  were  not  worked  extensively  until  1879. 

The  Bertha  mines,  situated  about  20  miles  southwest  of  Pulaski,  occur 
in  magnesian  limestone  of  the  Lower  Silurian  formation,,  which  dips  be- 
tween 6°  and  7°  toward  the  river  and  carries  the  zinc  bearing  strata  below 
the  latter  at  a  depth  of  several  hundred  feet.  The  outcrop  of  this  lime- 
stone is  covered  with  a  heavy  bed  of  clay,  beneath  which,  resting  in  hollows 
in  the  limestone,  the  zinc  ore  is  found.  Apparently  the  outcrop  of  the 
limestone  has  weathered  with  extreme  irregularity,  so  that  if  the  overlying 
clay  and  ores  were  entirely  removed  there  would  be  presented  a  wilderness 
of  limestone  pinnacles  of  varying  heights,  up  to  100  ft.  Rarely  the  lime- 
stone shows  small  caves  in  the  form  of  clefts  and  crevices.  The  deposits  of 
zinc  ore  invariably  rest  against  the  sides  of  these  pinnacles  and  in  Mie  hol- 
lows between  them.  Sometimes  they  completely  cover  a  pinnacle,  par- 
ticularly the  lower  ones,  but  in  general  they  cover  them  only  partially. 
The  occurrence  of  the  ore  is  irregular  and  frequently  pinnacles  and  the 
hollows  between  them  show  none  at  all.  The  ore  is  smithsonite  and  hemi- 
morphite,  chiefly  the  latter,  in  a  clay  gangue.  The  deposits  vary  in  thick- 
ness from  a  few  inches  up  to  40  ft.,  the  latter  having  been  found  between 
chimneys  (pinnacles).  On  the  sides  of  the  pinnacles  thicknesses  of  5  to 
10  ft.  occur  frequently,  but  the  average  is  less  than  5  ft. 

Character  of  the  Ore. — The  ore  consists  of  hard  and  soft  varieties,  the 
former  occurring  through  the  mass  in  all  sizes  from  small  grains  up  to 
blocks  weighing  several  tons.  Rarely  the  hard  zinc  ore  clings  to  the  lime- 
stone in  sheet  form.  The  ore  bodies  are  entirely  distinct  from  the  over- 
lying clay  and  underlying  limestone.  The  matrix,  or  gangue  in  which 
the  ore  occurs,  is  a  soft  unctuous  clay,  both  hard  and  soft,  the  former  being 
known  as  "hard  buckfat,"  and  the  latter  as  "soft  buckfat."  The  latter  dis- 
solves in  water  when  violently  agitated ;  the  former  is  insoluble,  but  having 
a  fine  grained,  brittle  structure,  like  common  chalk,  and  a  lower  specific 
gravity  than  the  hard  ore,  can  be  separated  by  jigging. 

The  ore  raised  from  the  mines  contains  about  26%  Zn.  It  is  dressed  by 
sluicing,  which  washes  out  a  good  deal  of  soluble  clay,  and  by  jigging,  so 
as  to  yield  about  33%  of  concentrate,  which  assays  38-08%  Zn,  20-37% 


202  PRODUCTION  AND  PROPERTIES  OF  ZINC. 


Si02,  9-23f0  Fe208  and  A1203,  -i-54%  CaC08,  2-W%  MgC03  and  8-23% 
combined  water.  This  ore  yields  a  spelter  of  exceptional  purity. 

Blende  is  found  in  irregular  deposits  through  a  depth  of  a  hundred 
feet  or  more  of  the  limestone  underlying  the  calamine,  and  in  following 
the  limestone  on  its  dip  it  is  expected  that  larger  deposits  will  be  found. 

Method  of  Mining.  —  The  Bertha  zinc  deposits  and  the  method  of  work- 
ing them  have  been  described  by  William  H.  Case  in  Trans.  Am.  Inst.  Min. 
Eng.,  XXII,  511  to  536,  and  by  B.  C.  Moxham  in  The'  Engineering  and 
Mining  Journal,  1893,  LVI,  No.  22.  Since  those  publications,  however, 
the  system  of  exploitation  has  been  changed  radically. 

The  thickness  of  the  clay  cover  varies  from  10  ft.  to  150  ft.  In  the 
early  days  of  the  mine  the  method  of  working  was  simply  to  remove  and 
waste  this  clay  covering  and  then  mine  the  ore  by  open-cut  methods.  Of 
late  years,  owing  to  the  increasing  thickness  of  this  overburden,  under- 
ground methods  of  mining  have  been  used  exclusively  and  the  open-cut 
work  abandoned;  these  underground  methods  consisted  of  sinking  shafts 
through  the  clay  and  zinc  ore  to  the  bed-rock  and  then  removing  the  zinc 
ore  by  drifts  and  galleries,  hoisting  the  ore  through  shafts,  and  of  course 
timbering  every  foot  of  the  ground  to  support  the  overburden.  In  still 
more  recent  times  two  important  and  determinative  circumstances  arose 
which  led  to  another  change  in  the  method  of  mining:  (1)  the  increas- 
ing expense  of  winning  the  zinc  ore  by  the  underground  methods  described 
above  made  them  quite  unsatisfactory;  and  (2)  the  clay  overburden  was 
discovered  in  a  greater  part  of  the  mineral  zone  to  be  capable  of  yielding 
a  high-class  limonite  ore,  which  was  valuable  for  its  iron  content. 

In  1898,  therefore,  the  mining  of  zinc  ore  on  the  property  was  abandoned 
temporarily  and  the  work  of  stripping  and  washing,  by  the  ordinary 
methods  of  the  district,  all  of  this  overlying  iron  ore  bearing  material  was 
begun.  In  1900  such  progress  had  been  made  that  about  1,300  tons  of  clay 
were  being  removed  and  washed  per  day,  yielding  about  160  tons  of  limonite 
which  is  shipped  to  the  blast  furnace  at  Pulaski,  the  idea  being  to  attack 
again  the  deeper  zinc  ore  by  open  cuts  whenever  and  wherever  the  cover  of 
clay  and  iron  shall  have  been  sufficiently  removed.  For  this  reason  the 
zinc  output  of  the  Bertha  Zinc  &  Mineral  Co.  has  been  temporarily  reduced. 

Clark  Mine.  —  Some  developments  have  been  made  at  the  Clark  mine, 
across  the  New  Eiver  from  Allisonia,  Pulaski  County,  Va..  where  calamine 
and  blende  have  been  found  over  a  considerable  area.  The  country  rock  is 
limestone  interstratified  with  dolomite,  in  which  large  beds  of  mineralized 
rock  are  said  to  occur.  A  test  of  a  carload  in  1898  showed  that  3-12  tons 
of  rock  would  yield  one  ton  of  concentrate  assaying  48%  Zn  and  16%  Pb. 


OCCURRENCE    OF    ZINC    ORE    IN    NORTH   AMERICA.  203 

Another  test  of  10  tons  of  rock  gave  245  tons  of  concentrate  assaying 
40-52%  Zn,  16-05%  Pb,  2-75%  Fe,  20-54  S,  and  1-8  oz.  silver  per  2,000  Ib.1 

WISCONSIN  AND  IOWA. — The  mines  of  these  States,  where  lead  occurs  in 
association  with  zinc,  were  first  worked  for  the  former  metal  a  little  previous 
to  1800;  the  mining  of  zinc  ore  did  not  begin  until  1860,  at  which  time 
the  establishment  of  the  Matthiessen  &  Hegeler  zinc  works  at  Lasalle, 
111.,  began  to  furnish  a  near-by  market  for  that  kind  of  ore.  The  area  of 
the  Wisconsin-Iowa-Illinois  mining  region,  which  for  convenience  will  be 
referred  to  as  the  "Wisconsin  region,"  including  under  that  expression  its 
extensions  into  Iowa  and  Illinois,  embraces  about  2,600  square  miles,  its 
length  in  an  east  and  west  direction  being  about  65  miles,  and  its  breadth 
north  and  south  about  55  miles,  the  area  being  more  or  less  elliptical  in 
plan.  About  five-sixths  lie  in  Wisconsin  and  one  sixth  covers  the  con- 
tiguous corners  of  Iowa  and  Illinois.  The  altitude  of  the  region  is  between 
580  and  1,700  ft.  above  sea  level,  its  surface  aspect  being  that  of  a  gently 
undulating  plain,  with  conical  flat-top  mounds  rising  100  to  400  ft.  above 
the  general  level. 

Geology. — The  geological  formation  comprises  sandstones,  limestones 
and  shales  of  the  Cambrian  and  Lower  Silurian  systems,  the  ore  being 
found  in  the  Galena  dolomite,  250  to  275  ft.  thick,  the  blue  limestone, 
50  to  75  ft.  thick,  immediately  underlying,  and  the  buff  dolomite,  15  to  20 
ft.  thick,  which  next  underlies  the  blue  limestone,  the  three  formations 
belonging  to  the  Lower  Silurian.  The  Galena  limestone  is  the  most  impor- 
tant ore  carrier. 

Geographically,  lead  ores  are  distributed  over  the  whole  region,  but  espe- 
cially in  the  southern  portion,  in  the  vicinity  of  Galena,  111.,  and  Dubuque, 
la.,  while  zinc  ore  is  more  abundant  in  the  northeast,  at  and  near  Mineral 
Point,  Mifflin,  Linden  and  Dodgeville,  where  the  lower  beds  of  the  ore 
bearing  horizon  are  more  exposed.  It  is  a  generally  observed  rule  in  this 
region  that  the  zinc  ore  occurs  at  greater  depth  than  the  lead  ore,  even 
when  both  are  found  in  the  same  crevice,  and  it  is  considered  possible  by 
the  geologists  who  have  studied  the  region  that  deeper  mining  would  reveal 
zinc  ore  in  the  southern  portion.  Besides  the  places  named  above,  Platte- 
ville,  Shullsburg,  Benton,  Hazel  Green  and  Potosi  are  important  mining 
centers. 

The  ore  first  mined  in  the  Wisconsin  region  was  found  chiefly  in  residu- 
ary clays  near  the  surface,  but  since  then  it  has  been  obtained  from  vertical 
crevices  or  flat  sheets  in  the  country  rock.  The  former  characterize  espe- 
cially the  Galena  limestone  and  are  preeminently  lead  bearing.  They  rarely 

1  The  Mineral  Industry,  VII,  729. 


204  PRODUCT JOX    AND    J'KOl'KUTTES    OF    ZINC. 

exceed  100  ft.  in  depth,  but  are  often  several  hundred  feet  in  length.  They 
sometimes  exist  as  fine  seams  filled  solidly  with  galena,  and  elsewhere  expand 
to  large  caves,  50  or  100  ft.  long  and  as  much  as  30  ft.  wide.  Flat  sheets 
are  most  abundant  in  the  Trenton  limestone,  and  like  the  vertical  crevices 
may  be  filled  with  solid  masses  of  galena  or  blende,  but  more  often  the 
mineral  is  intermixed  with  a  gangue  of  calcite  and  sometimes  barite.  A 
modification  of  the  flat  deposits  are  the  so-called  "flats  and  pitches,"  in 
which  ore  extends  downward,  generally  on  two  sides,  from  a  central  flat 
sheet  in  a  series  of  steps,  which  are  alternately  transverse  to  and  parallel 
with  the  strata.  The  largest  mines  are  in  deposits  of  this  class. 

Kinds  of  Ore. — The  zinc  ores  of  Wisconsin  comprise  blende,  smithsonite 
and  hemimorphite,  Avith  which  are  associated  galena  and  its  derivatives, 
pyrite,  marcasite,  chalcopyrite,  calcite,  dolomite  and  barite.  The  blende 
is  characteristically  of  a  black  color  and  is  consequently  apt  to  be  rather 
high  in  isomorphous  FeS.  Calcite  is  more  common  than  dolomite  and 
barite  in  the  gangue,  and  as  oxidation  product  of  the  blende,  smithsonite 
is  a  good  deal  more  common  than  hemimorphite.  According  to  Winslow, 
in  the  report  of  the  Missouri  Geological  Survey  on  Lead  and  Zinc,  I,  148, 
the  production  of  zinc  ore  in  Wisconsin  from  1860  to  1876,  both  years 
inclusive,  was  69,467  tons  of  smithsonite  and  57,728  tons  of  blende.  Since 
1890,  the  production  of  all  kinds  of  ore  appears  to  have  been  from  15,000 
to  20,000  tons  per  annum. 

Mining  Conditions. — The  methods  of  mining  in  vogue  in  Wisconsin  are 
crude,  nine  tenths  of  the  mines  being  worked  by  horse  and  man  power.  Until 
a  few  years  ago  there  was  no  thought  of  mining  below  what  was  then  the 
water  level,  but  during  the  last  30  to  40  years  the  water  has  fallen  10  to 
15  ft.  and  has  permitted  shafts  to  be  sunk  that  additional  distance.  It  is 
between  the  old  and  the  new  water  levels  that  most  of  the  blende  has  been 
mined.  Some  of  the  ore  mined  in  Wisconsin  is  jigged,  but  a  good  deal  is 
concentrated  by  hand  sorting  only  and  is  marketed  in  lump  form.  Out  of 
12,500  tons  of  ore  sold  in  nine  years  from  one  mine  at  Benton  77%  was 
sorted,  lump  ore.  A  good  deal  of  low  grade  ore  is  said  to  have  been  left 
in  some  of  the  mines  because  of  lack  of  machinery  for  handling  it.  The 
Wisconsin  region  is  considered  by  many  persons  to  have  a  capacity  for  a 
larger  output  of  zinc  ore  than  at  present  is  made  if  more  attention  were 
devoted  to  it,  but  the  presence  of  a  considerable  percentage  of  marcasitc 
mixed  with  the  blende  makes  the  production  of  a  high  grade  concentrat< 
difficult  in  many  cases,  and  the  larger  deposits  and  more  docile  ores  of  the 
Joplin  district  make  the  latter  more  attractive  to  miners. 


OCCURRENCE  OF  ZINC  ORE  IN  NORTH  AMERICA.  205 

OCCURRENCE  OF  ZINC  ORE  IN  CANADA  AND  MEXICO. 

CANADA. — Deposits  of  zinc  ore  on  the  north  shore  of  Lake  Superior  at- 
tracted attention  in  1898,  when  the  Grand  Calumet  Mining  Co.  began  the 
exploitation  of  a  vein  of  blende  near  Eossport  in  the  Algoma  district.  The 
investment  of  capital  in  that  enterprise  stimulated  prospectors  to  a  more 
diligent  search  for  new  deposits,  with  encouraging  results  according  to  the 
report  of  the  Bureau  of  Mines  of  Ontario  for  1900.  The  Zenith  mine, 
owned  by  the  Grand  Calumet  Mining  Co.,  is  situated  about  12  miles  north 
of  Rossport,  a  small  town  on  the  line  of  the  Canadian  Pacific  Railway,  the 
road  to  the  mine  leaving  the  railway  five  miles  east  of  Rossport.  The 
country  is  extremely  rough  and  access  to  the  mine,  which  is  about  1,200  ft. 
in  elevation  above  the  level  of  the  railway,  is  difficult,  and  the  road,  crossing 
twelve  small  lakes,  shipments  can  be  made  under  present  conditions  only 
in  winter,  when  the  lakes  are  frozen  over. 

The  Zenith  mine  is  opened  on  a  lode  intersecting  a  trap  formation.  This 
lode,  which  stands  nearly  vertical,  is  continuous  on  the  surface  for  a  con- 
siderable distance,  but  although  it  presents  a  good  showing  of  ore  at.  some 
places,  the  ore  is  said  not  to  extend  to  much  depth,  so  far  as  has  been  yet 
discovered.  The  ore  is  blende,  dark  in  color,  occurring  mixed  with  country 
rock,  which  is  separated  by  cobbing,  whereby  a  product  assaying  about  50% 
Zn  is  produced.  The  cost  of  transportation  from  the  mine  to  the  railway 
is  about  $2  per  2,000  Ib ;  according  to  the  report  of  the  Ontario  Bureau  of 
Mines  for  1900,  it  is  not  probable  that  the  cost  of  carting  will  ever  be 
reduced  unless  very  great  quantities  of  ore  be  discovered  in  the  district, 
since  the  cost  of  building  any  kind  of  a  railroad  through  a  country  of  such 
difficult  topography  would  be  prohibitory.  Some  prospecting  has  been 
done  on  properties  near  the  Zenith  mine,  where  apparently  similar  occur- 
rences of  ore  have  been  discovered.  The  total  production  of  zinc  ore  in 
Ontario  in  1899  was  reported  by  the  Ontario  Bureau  of  Mines  as  amounting 
to  1,200  tons  of  2,000  Ib.,  valued  at  $24,000,  all  of  which  was  derived 
from  the  Zenith  mine.  At  the  end  of  1900  the  company  operating  that 
mine  had,  according  to  Tlie  Engineering  and  Mining  Journal,  of  Jan.  12, 
1901,  about  2,000  tons  of  50%  ore  ready  for  shipment,  which  probably  rep- 
resented the  production  of  1900. 

MEXICO. — Zinc  blende  occurs  at  numerous  places  in  this  Republic,  but 
many  of  the  deposits  are  so  remote  that  they  are  unworkable  under  present 
conditions.  A  few  are  more  favorably  situated.  Near  Monterey  there  is 
said  to  be  a  mine  of  high  grade  blende  ore,  nearly  free  from  lead,  which 
assays  3  to  8  oz.  silver  per  ton.  At  Charcos,  San  Luis  Potosi,  there  are 


206  .  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

galena-blende  ores  assaying  12  to  40%  Zn  and  12  to  60  oz.  silver  per  ton. 
This  is  an  old  mining  district,  and  a  largely  worked  one,  where  the 
blende  was  avoided  or  sorted  out  and  thrown  on  the  waste  dumps  in  the 
previous  exploitations.  Similar  accumulations  of  rejected  zinc  ore  are  to 
be  found  elsewhere  in  Mexico.  At  Matehuala  and  Maroma,  in  San  Luis 
Potosi,  there  is  blende  associated  with  silver,  lead  and  copper  minerals. 
Other  zinc  bearing  districts  exist  in  the  states  of  Mexico,  Puebla,  Hidalgo 
and  Tamaulipas,  but  zinc  being  disliked  in  the  treatment  of  ores  for  copper, 
lead  and  the  precious  metals,  little  is  known  as  to  their  capacity  or  chances 
for  development.  In  1896  the  cost  of  transportation  from  Monterey  to 
Liverpool  or  Swansea  was  $15,  Mexican  currency,  per  metric  ton.  Charcos 
and  Maroma  have  good  railway  communication,  and  the  cost  from  those 
places  would  probably  be  only  a  little  more  than  from  Monterey.  The 
Helena  Mining  Co.  is  said  to  have  at  Cusihuiriachic,  Chihuahua,  large 
bodies  of  ore,  which  average  25%  Pb,  30%  Zn,  and  a  considerable  tenor  of 
silver.  A  sample  of  this  ore  assayed  264%  Pb,  35-5%  Zn,  5-6%  Fe, 
1-8%  Si02  and  7-5  oz.  Ag  per  ton. 


X. 

OCCURRENCES  OF  ZINC  ORE  IN  EUROPE,  AFRICA 
AND  AUSTRALIA. 

Deposits  of  zinc  ore  are  more  numerous  in  Larope  than  in  America,  if  the 
at  present  largely  non-available  resources  of  the  Rocky  Mountains  be  left 
out  of  account,  and  their  aggregate  production  is  larger.  Outside  of  Eu- 
rope there  is  an  important  production  in  Algeria  and  Tunis,  while  lately  a 
considerable  supply  of  ore  has  been  obtained  from  Broken  Hill,  New  South 
Wales,  where  the  blende  which  occurs  in  great  quantity  intimately  mixed 
with  galena  has  been  successfully  separated  under  favorable  market  condi- 
tions. The  zinc  resources  of  Europe  are  probably  now  well  known,  with 
the  exception  of  parts  of  Russia  which  are  too  remote  for  profitable  exploita- 
tion at  this  time.  Those  of  Asia,  Australasia,  Africa  and  South  America 
have  hardly  been  explored.  The  most  important  zinc  producing  countries 
of  Europe  are  Germany,  Italy,  France,  Spain  and  Sweden,  the  statistics  of 
which  countries,  together  with  others,  have  been  presented  in  Chapter  IV. 
It  should  be  remarked  that  the  great  preponderance  of  Germany  in  the  sta- 
tistics is  due  largely  to  the  fact  that  the  ore  of  Upper  Silesia  is  smelted  in  a 
comparatively  low  grade  form,  while  that  of  other  countries  is  mostly  con- 
centrated. 

ZINC  ORE  DEPOSITS  OF  EUROPE. 

The  geological  occurrence  of  some  of  the  important  deposits  of  zinc  ore 
in  Europe  is  summarized  in  the  following  table,  which  is  admittedly  very 
incomplete,  but  is  of  some  interest  in  showing  the  general  tendency  of  zinc 
ore  deposits  to  form  in  a  country  rock  of  limestone  or  dolomite.  The  same 
phenomenon  is  manifested  in  the  case  of  the  principal  non-argentiferous 
deposits  of  the  United  States,  which  were  summarized  in  tabular  form  on 
page  179.  It  will  be  observed  in  comparing  the  two  statements  that  the 
zinc  ore  deposits  of  Europe  occur  through  a  wider  geological  horizon  than 
do  those  of  America,  being  found  in  rocks  from  the  Laurentian  age  up  to 

207 


208 


PRODUCTION    AND    PROPERTIES    OF   ZINC. 


those  of  the  Cretaceous,  whereas  the  American  deposits  are  chiefly  in  Lower 
Carboniferous  and  Silurian  formations. 


Country. 

District. 

Character  of 
Mineral. 

Country  Hock. 

Age. 

Belgium  
France  

Moresnet. 
Les  Malines. 

Upper  Harz. 
Gladbach 
Iserlohn. 
Upper  Silesia. 

Cumberland. 
Shropshire. 
Laurmm 

Iglesias. 
Poland. 

Cartagena. 
Reocin. 

Ammeberg. 

Calamine. 
Calamine  and 
blende. 
Blende, 

Calamine. 

Calamine  and 
blende. 
Calamine  and 
blende. 
Blende. 
Blende. 
Calamine  and 
blende. 
Calamine. 

Calamine  and 
blende. 
Blende. 
Calamine  and 
blende 
Blende. 

Dolomite. 
Dolomite. 

Slate. 

Dolomite   and 
shale. 
Limestone  and 
shale. 
Dolomite. 

Limestone. 
Slate  and  shale 
Limestone  and 
mica  schist. 
Limestone  and 
schist. 
Dolomite. 

Schist. 
Dolomite. 

Gneiss. 

Carboniferous. 
Jurassic. 

Devonian  and  Lower 
Carboniferous. 
Devonian. 
. 
Devonian. 

Triassic. 

Lower  Carboniferous. 
Cambrian-Silurian. 
Silurian. 

Silurian. 
Triassic, 

Cretaceous    and  Ju- 
rassic. 
Laurentian. 

4< 

Great  Britain  .  . 
« 

Greece    

Italy  

Russia 

Spain  .... 

Sweden  

AUSTRIA. — The  principal  zinc  mines  of  Austria  are  situated  in  Southern 
Carinthia,  Styria  and  the  Tyrol.  The  Carinthian  deposits  are  distributed 
in  a  belt  a  few  miles  wide  and  about  100  miles  long  in  an  east  and  west 
direction.  The  chief  mines  are  at  Bleiberg,  Kreuth,  Kaibl,  Windisch-Blei- 
berg,  Kappel,  Miess  and  Schwarzenberg.  The  country  rock  is  limestone 
and  dolomite  of  Triassic  age  in  which  are  found  bodies  of  ore  of  irregular 
form,  their  axes  appearing  to  follow  the  intersections  of  stratification  planes 
and  fault  fissures.  Such  pipe-shaped  deposits  have  been  as  much  as  1,200 
ft.  long  and  from  6  to  90  ft.  in  diameter.  Sometimes  they  spread  out  on 
the  stratification  planes  of  the  country  rock,  forming  flat  lenses  as  much  as 
20  ft.  in  thickness.  The  ore  is  chiefly  galena,  but  blende  occurs  with  it,  and 
in  places  bodies  of  smithsonite  are  found. 

In  the  Tyrol  zinc  is  mined  at  Schneeberg,  where  the  mines  which  had 
been  worked  for  many  centuries  and  exhausted  of  their  lead  ore  were  re- 
opened for  zinc  in  1866.  The  mines  are  opened  on  lodes  7  to  56  ft.  thick, 
which  have  been  followed  on  their  strike  a  distance  of  1-5  miles  and  to  a 
depth  of  3,000  ft.  The  country-rock  is  mica  schist  and  the  ore  is  blem 
and  galena,  with  some  pyrite  intermixed. 


OCCT1U5EXCES    OF    ZINC    ORE    IN    Et'KOrE,    AFRICA    AND   AUSTRALIA     201) 

BELGIHI  AND  MORESNET. — Belgium  was  formerly  a  large  producer  of 
zinc  ore,  but  since  1856  its  output  has  steadily  decreased  and  is  now  com- 
paratively unimportant.  Its  mines  are  of  great  historic  interest,  however, 
having  been  the  first  exploited  in  the  world  for  zinc  and  established  a  great 
smelting  industry,  which  now  maintains  its  importance  by  the  importation 
of  foreign  ores.  The  principal  zinc  deposits  of  Belgium  occur  at  Bleyberg, 
and  near  Yerviers  and  Liege  in  the  Province  of  Liege.  In  the  neutral 
territory  of  Moresnet1  are  the  famous  mines  of  the  Vieille  Montagne. 

Moresnet. — The  zinc  mines  of  Altenberg,  or  Vieille  Montagne,  are  be- 
iieved  to  have  been  worked  as  early  as  the  twelfth  century,  though  the  first 
reference  to  them  in  existing  documents  is  1435.  Extensive  mining  was 
begun  in  1846,  by  open  cuts,  and  in  1856  underground.  Up  to  1878  the 
total  output  was  1,600,000  tons  of  concentrated  ore,  derived  from  200,- 
000,000  of  crude  ore.  The  deposit  existed  in  a  narrow  synclinal  basin  in 
Carboniferous  dolomite,  walled  in  by  Devonian  shales  standing  nearly  ver- 
tically. The  deposit  was  about  1,400  ft.  long,  600  to  700  ft.  wide  and  200 
ft.  deep.  The  ore  was  chiefly  smithsonite  and  hemimorphite,  replacing  com- 
pletely the  dolomite  in  some  places.  Intercalated  strata  and  masses  of  dolo- 
mite occurred,  however,  and  one  such  horse  divided  the  ore  body  in  two 
parts.  The  mineral  was  generally  distributed  irregularly,  but  sometimes 
was  found  in  compact  masses  and  sometimes  in  layers  separated  by  clay. 
Besides  the  smithsonite  and  hemimorphite,  willemite  occurred  in  masses  as 
large  as  100  cu.  yds.  The  smithsonite  was  more  abundant  in  the  upper 
portions  of  the  deposit  and  the  hemimorphite  in  the  lower,  the  willemite 
being  promiscuously  distributed.  But  very  little  blende  or  galena  was 
found.  The  Vieille  Montagne  mine  has  been  owned  since  the  early  part 
of  this  century  by  the  Societe  Anonyme  de  la  Vieille  Montagne,  which  takes 
its  name  from  it.  The  mine  is  still  operated,  but  its  production  is  no 
longer  large. 

Bleyberg. — The  mine  at  Bleyberg,  near  Altenberg,  which  has  also  been 
a  large  producer,  but  to  a  far  less  extent  than  the  Vieille  Montagne,  is 
opened  on  a  fissure  vein  about  3  ft.  thick,  which  traverse?  Lower  Carboni- 
ferous limestone  and  Coal  Measure  shales,  sandstones  and  grits,  having  been 
proved  for  a  distance  on  its  strike  of  1-5  miles  in  the  former  and  three  miles 
in  the  latter.  The  vein  stands  vertically,  or  dips  at  an  angle  of  75°  to  80°. 
The  vein  matter  consists  chiefly  of  broken  country  rock  carrying  about  18% 
of  metalliferous  minerals,  principally  blende  and  galena  which  exist  in 

1  This  belongs  neither  to  Belgium  or  Ger-        sented  in  the  official  statistics  published  by 
many,    between    which    countries    It    Is    sit         any    government, 
uated      Its  mineral  production  is  not  repre- 


210  PRODUCTION    AND   PROPERTIES    OF   ZINC. 

nearly  equal  proportions.  At  certain  places  large  cavities  have  been  coi 
roded  in  the  adjacent  limestone,  as  much  as  1,600  ft.  in  length  and  200  ft 
in  width,  which  were  lined  with  blende  and  galena,  but  through  movement 
in  the  rock  those  incrustations  were  dislodged  and  buried  in  a  mass 
breccia  on  the  floor  of  the  caverns.  The  Bleyberg  mine  is  very  wet. 

Welkenrodt. — At  Welkenrodt,  near  Altenberg,  a  bed  of  zinc  ore  occu] 
between  limestone  and  shale  of  Carboniferous  age.  Along  its  strike  it  m< 
ured  about  750  ft.  The  lower  portion  of  the  ore  body,  next  to  the  lime- 
stone (foot  wall),  was  an  earthy  variety  of  hemimorphite  passing  into  an 
ochery  iron  ore  in  the  upper  levels.  The  upper  portion,  next  the  shale 
(hanging  wall)  was  a  black  clay  containing  nodules  and  seams  of  blende, 
galena  and  pyrite.  The  deposit  dipped  steeply  and  conformed  to  the  bends 
of  the  enclosing  rocks. 

Nouvelle  Montague. — At  Verviers  the  Nouvelle  Montagne  mine  was 
opened  on  a  large  pear  shape  body  of  zinc  ore  surrounding  a  core  of  dolomite. 

Corphalie. — At  Corphalie,  near  Liege,  beds  of  hemimorphite,  blende  and 
galena,  from  3  to  25  ft.  thick,  standing  nearly  vertically,  occurred  between 
Lower  Carboniferous  limestone  and  Coal  Measure  rocks. 

Philippeville. — Contact  beds  of  galena  and  blende  in  the  form  of  in- 
clusions in  limestone  were  worked  at  Philippeville,  one  impregnated  stratum 
of  dolomite  being  traceable  for  two  miles. 

FRANCE. — The  production  of  zinc  ore  in  this  country  which  began  about 
1870  has  increased  heavily  since  1885.  The  more  part  of  the  ore  is  cala- 
mine.  It  is  mined  chiefly  in  Southern  France,  in  the  region  embraced  be- 
tween the  Alps  and  the  Pyrenees.  The  mines  of  the  Department  of  Gard  are 
the  chief  producers,  affording  nearly  50%  of  the  total  production  of  France. 
The  Department  of  Var  ranks  in  importance  next  after  Gard.  Inasmuch 
as  the  names  of  the  modern  departments  into  which  France  is  divided  con- 
vey an  idea  of  their  geographical  position  to  only  a  few  who  are  not  French- 
men, I  have  grouped  the  zinc  mines  of  the  Republic  according  to  the  ancient 
provinces,  or  governments. 

Angoumois. — Deposits  of  mixed  sulphide  ore  occur  at  Alloue  and  Amber- 
nac,  in  the  valley  of  the  Charente,  near  Angouleme.  A  sample  of  the  ma- 
terial smelted  experimentally  by  the  Ellershausen  process  assayed  21-1% 
Zn,  11-3J&  Pb,  6-19&  FeO,  10-8J6  8,27-2%  Si02,  1-7%  CaO,  4-1%  BaO, 
0-1%  A1203,  0-07%  As,  0-15%  Sb,  and  243  oz.  Ag  per  ton. 

Brittany. — The  mines  of  Pontpean,  near  Rennes,  in  the  Department  of 
Ille-et-Vilaine,  are  the  most  important  in  the  Province  of  Brittany.  They 
are  opened  on  a  vein,  attaining  sometimes  a  width  of  25  ft.  and  averaging 
about  7  ft.,  which  cuts  vertically  through  Silurian  schists.  It  has  been 


OCCURRENCES    OF    ZINC    ORE    IN    EUROPE,    AFRICA    AND    AUSTRALIA.      211 

explored  to  a  depth  of  nearly  500  m.  The  ore  is  galena  and  blende,  both 
argentiferous,  and  pyrite,  occurring  as  seams  in  a  gangue  of  quartz  and  clay. 
In  1895  the  production  was  119,310  tons  of  crude  ore,  which  yielded  15,057 
tons  of  galena,  assaying  55%  Pb,  and  30,502  tons  of  galena-pyrite-blende. 

At  La  Tauche,  a  vein  in  granite  contains  galena  and  blende. 

Dauphiny. — ]STear  Merglon,  in  the  Piemart  Mountains  in  the  Depart- 
ment of  Drome,  pockets  of  smithsonite,  which  peter  out  with  depth,  are 
found  in  Middle  Jurassic  limestone.  There  is  also  a  vertical  vein,  some- 
times 30  ft.  between  walls,  which  is  filled  largely  with  calcite,  replaced  by 
smithsonite  in  places,  blende  and  galena  being  of  occasional  occurrence. 

Gascony. — Zinc  ore  is  produced  in  numerous  departments  of  the  Pyre- 
nees. In  the  Canton  of  Castillon,  Ariege,  the  Sentein  mines  are  opened  on  a 
lode  between  Lower  Carboniferous  limestone  (foot  wall)  and  schist  (hang- 
ing) ;  the  ore  is  argentiferous  galena,  cerussite,  anglesite,  blende  and  cala- 
mine,  with  gangue  of  quartz  and  calcite.  The  mines  are  at  elevation  6,888 
ft.  The  lode  is  traceable  a  great  distance  along  the  ridge  of  the  mountains. 
Near  St.  Girons  there  are  veins  carrying  blende,  siderite,  argentiferous 
galena,  calcite  and  quartz.  In  the  Department  of  Haute  Garonne,  near 
Arguts,  numerous  thin  veins  of  blende,  with  some  galena,  traverse  Silurian 
slates  and  schists.  There  are  deposits  of  zinc  ore  in  the  departments  of 
Haute  and  Basse  Pyrenees,  which  produce  several  thousand  tons  per  annum. 

Languedoc. — At  Les  Malines  in  the  Department  of  Gard  there  are  two 
classes  of  deposits.  The  more  important  occur  in  dolomite  of  Middle  Juras- 
sic age,  in  and  along  crevices,  in  caves,  and  in  large  masses  inclosing  par- 
tially unaltered  pieces  of  the  country  rock.  The  ore  is  smithsonite,  hemi- 
morphite,  hydrozinkite,  anglesite,  pyromorphite,  blende  and  galena.  The 
other  form  of  deposit  is  a  large  vein  traversing  limestone,  which  has  been 
opened  on  its  outcrop  for  1,500  ft.  The  vein  consists  of  an  aggregate  of 
parallel  and  interlacing  fissures,  mineralized  with  blende,  galena,  pyrite 
and  barite.  The  production  of  Les  Malines  in  1894  was  17,100  tons  of 
calamine,  20,300  of  blende  and  1,000  of  galena.  At  Clairac,  near  Alais,  a 
series  of  fault  fissure  veins,  from  6  in.  to  3  ft.  wide,  leanly  mineralized 
with  blende  and  pockets  of  galena  and  carrying  barite,  traverse  Lower 
Jurassic  limestone.  The  Eoussan  group  includes  irregular  deposits  of 
mineralized  Jurassic  limestone  which  become  poor  with  depth.  At  Les 
Avinieres  a  deposit  of  calamine,  now  exhausted,  occurred  impregnating  a 
bed  of  dolomite  between  overlying  marl  and  an  underlying  bed  of  silicious 
dolomite.  Similar  deposits,  some  of  them  containing  blende,  occur  at  dif- 
ferent horizons  in  the  same  district.  In  the  Department  of  Ardeche,  which 
adjoins  Drome,  there  are  veins  of  blende  and  galena. 


212  PRODUCTION    AND   PROPERTIES    OF    ZINC. 

Provence. — In  the  Department  of  Var  there  are  deposits  of  calamine  and 
blende  which  make  a  considerable  production.  The  Bormettes  mine  is  the 
principal  producer;  its  output  in  1894  was  24,000  tons,  all  of  which  was 
blende. 

GERMANY. — This  Empire  possesses  the  only  single  zinc  mining  district 
which  in  point  of  production  approaches  the  Joplin  district  of  the  United 
States,  namely,  Upper  Silesia.  Besides  that,  however,  there  are  important 
zinc  mines  in  Ehineland  and  Westphalia,  while  considerable  quantities  of 
zinc  ore  are  obtained  from  the  mines  of  Nassau,  the  Harz,  and  elsewhere, 
which  are  also  worked  for  both  lead  and  zinc. 

Baden. — The  Grand  Duchy  of  Baden  no  longer  produces  zinc  ore,  but 
owing  to  their  great  historic  interest  space  may  be  spared  for  a  brief  refer- 
ence to  the  once  famous  mines  of  Weisloch,  in  the  northern  part  of  the 
Duchy,  which  were  worked  for  galena  as  early  as  the  eleventh  century.  The 
country  rock  there  is  limestone  and  dolomite  of  the  Muschelkalk  formation 
of  the  Lower  Triassic,  in  the  upper  beds  of  which  smithsonite, blende, galena,*1 
marcasite  and  limonite,  associated  generally  with  a  red  clay,  occurred  in 
irregular  enlargements  of  vertical  fissures  at  the  intersections  of  the  latter 
with  the  stratification  planes  of  the  limestones,  the  ore  bodies  extending  out 
along  those  planes  in  sheets,  pipes  and  irregular  masses,  sometimes  for  dis- 
tances of  2,000  ft.,  attaining  thicknesses  of  20  ft.  The  smithsonite  was 
remarkable  for  its  high  tenor  in  cadmium,  as  much  as  3-36%  of  that  metal 
having  been  reported. 

Hanover:  Upper  Harz. — A  considerable  quantity  of  blende  is  separated 
as  a  marketable  product  by  the  dressing  works  in  the  Upper  Harz,  where 
the  mines,  of  which  the  most  important  are  in  the  vicinity  of  Clausthal  and 
Lautenthal,  are  worked  chiefly  for  lead  and  silver.  The  ore  occurs  there  in 
veins  in  zones  of  crushed  slate  of  Devonian  and  Lower  Carboniferous  age, 
said  zones  being  65  to  262  ft.  (20  to  80  m.)  in  width  and  extending  longi- 
tudinally about  nine  miles  (15  km.).  The  ore  bodies  are  distributed  irregu- 
larly through  them.  The  rock  of  the  ore  zone  is  called  vein-clay-slate 
(Gangthonschiefer)  to  distinguish  it  from  the  ordinary  clay  slate  (Culm- 
schiefer)  of  the  region,  but  their  composition  is  identical,  the  former  having 
been  derived  from  the  latter,  chiefly  by  mechanical  alteration  due  to  the 
force  which  produced  the  great  faults  that  traverse  the  country  rock.  The 
Lautenthal  mines  are  particularly  productive  of  blende,  but  with  depth  in 
all  the  mines  the  proportion  of  that  mineral  increases  and  galena  decreases. 

Lower  Harz:  The  famous  ore  deposit  of  the  Eammelsberg,  near  Oker 
and  Goslar,  in  the  Lower  Harz,  first  worked  between  930  and  940  and  more 
or  less  continuously  ever  since,  occur?  as  a  bod  inter  stratified  with  Lower  "He- 


OCCURRENCES    OF    ZINC    ORE    IN    EUROPE.,    AFRICA   AND    AUSTRALIA.      213 

vonian  slates  and  sandstones,  which  have  been  overturned  so  that  the  original 
foot  wall  is  now  the  hanging.  The  ore  body,  which  conforms  to  the  struc- 
ture of  the  country  rock,  dips  about  45P.  In  the  direction  of  its  length  it 
has  been  exploited  over  1-5  miles  and  in  depth  nearly  1,000  ft.,  having  a 
general  thickness  of  50  ft.  At  its  maximum  development  it  was  1,900  ft 
wide  and  150  ft.  thick ;  at  the  depth  of  800  ft.  it  was  750  ft.  wide  and  20  ft 
thick. 

The  ore  is  an  intimate  mixture  of  blende,  galena,  pyrite,  chalcopyrite  and 
barite,  together  with  some  calcite  and  quartz.  It  is  sorted  at  the  mine  into 
two  classes:  (1)  copper  ore,  averaging  8  to  10%  Cu  and  (2)  zinc-lead  ore 
averaging  about  25%  Zn  and  12%  Pb.  The  mineralogical  composition  of 
the  latter  is  as  follows:  blende,  36%;  pyrite,  24%;  barite,  16%;  galenitey 
14%;  chalcopyrite,  1-5% ;  gangue,  8-5% ;  total,  100%.  The  copper  ore  is 
sent  to  the  smelting  works  at  Oker  and  the  zinc-lead  ore  to  the  Sophienhiitte 
at  Langelsheim  and  the  Juliushutte  at  Astfeld,  where  it  is  treated  first  for 
the  recovery  of  a  part  of  its  zinc  as  sulphate,  after  which  the  residue  is 
smelted  in  blast  furnaces  for  lead.  When  the  component  minerals  of  the 
Rammelsberg  ore  occur  in  distinct  bands,  which  is  sometimes  the  case,  the 
sorting  into  classes  is  facilitated. 

The  ore  deposits  of  Broken  Hill,  New  South  Wales,  Leadville,  Colo.,  and 
the  Rammelsberg  of  Hanover,  are  occurrences  of  mixed  sulphide  ores 
which  are  remarkable  for  their  size  and  high  metallic  contents.  The  Broken 
Hill  ore  is  essentially  galena  and  blende;  that  of  Leadville,  galena,  blende 
and  pyrite;  that  of  the  Rammelsberg,  galena,  blende,  pyrite  and  chalco- 
pyrite. In  each  case  the  minerals  are  argentiferous.  The  Broken  Hill  ore 
contains  about  66%  of  sulphides;  the  Rammelsberg,  about  75%;  and  that 
of  Leadville  upward  of  90%. 

Nassau. — There  is  an  important  lead  producing  district,  from  which  zine 
is  also  obtained,  in  the  valley  of  the  Lahn,  Duchy  of  Nassau,  where  a 
series  of  remarkably  strong  veins  are  found  in  a  graywacke  belonging  to  the 
Lower  Devonian  formation.  There  are  two  great  veins  on  which  several 
mines  are  opened.  One  of  these  extends  from  a  point  near  St.  Goar,  on  the 
west  bank  of  the  Rhine,  to  Holzappel,  on  the  Lahn,  at  which  point  it  is 
richest — a  distance  of  nearly  eight  miles.  The  other,  the  Ems  vein,  extends 
from  Braubach,  on  the  Rhine,  across  the  valley  of  the  Lahn  to  Deerbach, 
near  Montabaur.  The  most  important  mines  are  situated  at  Holzappel, 
where  they  are  operated  by  the  Rheinisch-^Tassauische  Bergwerks-  und  Hiit- 
tenactiengesellschaft,  and  near  Ems,  where  they  are  operated  by  the  Emser 
Blei-  und  Silberwerke  and  the  Silber-  und  Bleibergwerk  "Friedrichssegen." 

The  mines  at  Holzappel,  which  have  been  exploited  since  1785,  had  in 


214  PRODUCTION"  AND  PROPERTIES  OF  ZINC. 

1892  been  opened  continuously  on  the  strike  of  the  vein  for  a  distance  of 
11,480  ft.  (3,500  m.).  In  general  the  ore  of  the  Lahn  is  a  complicated 
mixture  of  silver-bearing  galena,  blende,  siderite,  barite,  calcite  and  quartz. 
It  is  concentrated  in  the  dressing  works  at  Laurenberg,  Silberau  and 
Friedrichssegen,  which  rank  among  the  largest  in  Germany.  The  crude  ore 
received  at  the  Silberau  works  averages  4%  Pb,  2-5%  Zn  and  54  g.  silver 
per  1000  kg.  The  galena  is  concentrated  to  36%  Pb  with  300  g.  silver  per 
metric  ton,  and  the  blende  to  44-5%  Zn;  the  blende  does  not  carry  silver. 
The  loss  in  dressing  is  8%  for  silver,  6%  for  lead  and  34%  for  zinc.1  The 
cost  of  dressing  is  about  85c.  per  metric  ton  of  crude  ore. 

The  mines  at  Friedrichssegen  produce  argentiferous  galena,  argentiferous 
chalcopyrite,  pyrite,  blende  and  siderite,  with  a  quartzose  gangue,  which  are 
classified  by  hand  sorting  and  gravity  concentration.  The  class  of  concen- 
trates which  is  a  mixture  of  blende  and  siderite,  and  assays  about  15% 
Zn  and  27%  Fe,  is  calcined2  and  treated  magnetically,  yielding  a  product 
assaying  37  to  42%  Zn,  and  at  the  most  6%  Fe,  which  is  sold  to  zinc 
smelters,  and  an  iron  ore  assaying  40%  Fe  and  less  than  4%  Zn  which  is 
sold  to  iron  smelters  (vide  Chapter  XI). 

Rhenish  Prussia. — Deposits  of  zinc  ore  occur  at  several  places  in  Rhenish 
Prussia.  At  Gladbach,  east  of  Cologne,  they  are  found  in  troughs  and 
basins  in  magnesian  limestone  of  Devonian  age,  having  the  appearance  of 
having  been  washed  in  mechanically.  They  are  covered  by  later  deposited 
beds  of  clay  and  shale,  which  contain  brown  coal.  The  ore  is  smithsonite, 
hemimorphite  and  galena  mixed  with  shale.  The  mines  of  the  Societe 
Anonyme  de  la  Yieille  Montagne  at  Bensberg,  near  Gladbach,  are  very  im- 
portant. Their  product  is  chiefly  blende.  At  Altgllick  a  bed  of  blende  is 
intercalated  in  Lower  Devonian  shales  and  sandstones.  The  ore  carries  some 
galena  and  has  a  quartzose  gangue.  With  depth  the  deposit  splits  up  and  • 
diffuses.  Veins  of  blende  striking  in  various  directions  occur  in  the  Eifel 
district  of  the  Moselle,  in  Lower  Devonian  rocks.  At  the  intersections  they 
show  enrichments.  Deposits  of  blende  are  also  found  at  Siebengebirge,  on 
the  eastern  side  of  the  Rhine  below  Coblentz. 

Saxony. — The  historic  mines  of  Freiberg  produce  a  small  quantity  of 
blende  in  connection  with  galena  and  other  minerals,  which  come  from  the 
remarkable  series  of  intersecting  veins,  seldom  more  than  2  ft.  in  width, 
but  more  than  900  in  number,  which  traverse  gneiss.  Mining  was  begun 
there  as  early  as  the  twelfth  century.  The  blende  of  Freiberg  is  of  the  black, 

1  M.  Bellom,  "Preparation  M£canique  des       No.  4,  pp.  82  and  91. 

Minerals    dans    la    Saxe,    le    Hartz,    et    la  » The  heat   attained   Is  not   sufficient 

Prusse  Rhe"nane,"  Annales  des  Mines,  1891.       desulphurize  the  blende. 


OF  ZINC  OKI-:  ix  EintopE,  AFIUCA  AND  AUSTRALIA.    215 


shining  variety  and  is  remarkably  high  in  combined  monosulphide  of  iron;  it 
is  also  argentiferous.  The  ore  raised  from  the  mines  is  concentrated  in  the 
Himmelfahrt  works,  which  produce  besides  galena  and  other  products  a 
zinc  ore  (blende)  assaying  40%  Zn  and  300  g.  silver  per  metric  ton.  This 
blende  is  smelted  in  a  department  of  the  Muldnerhiitte,  and  the  residues  are 
sent  to  the  lead  furnaces  for  recovery  of  their  silver  contents. 

Upper  Silesia.  —  The  zinc  deposits  of  Upper  Silesia  occur  in  the  extreme 
southeastern  corner  of  the  Province,  near  where  the  three  empires  of  Ger- 
many, Russia  and  Austria  meet.  They  extend  into  Russia,  but  the  greater 


MEASURES          \\  RUSSIA 

'»         (BARREN)        \   >          Government  Petrokow 

'  I 


,*^  SANDSTONE 

^C«3ALVEASURES  ^ 


c->x- — ?r\ 


FIG.  18. — MAP  OF  THE  ZINC  MINING  DISTRICT  OF  UPPER  SILESIA. 

Scale,  1 :1 20,000. 

part  of  the  mineral  district  lies  in  Germany.  This  entire  region  was  for- 
merly a  part  of  the  Kingdom  of  Poland,  and  at  the  present  time  the  popula- 
tion in  both  the  German  and  Austrian  divisions  is  chiefly  Polish.  Lead  was 
mined  there  as  early  as  the  twelfth  century  and  zinc  ore  in  the  sixteenth. 

Geology, — The  lead  and  zinc  deposits  occur  in  the  Muschelkalk  series  of 
the  Triassic  formation,  which  rest  on  the  Bundsandstein  of  the  same  forma- 
tion, the  latter  overlying  Carboniferous  rocks.  The  coal  measures,  which 
carry  powerful  seams  of  coal,  come  near  the  surface  a  short  distance  south 


216  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

of  the  zinc  mining  district,  forming  a  conjunction  between  ore  and  fuel 
similar  to  that  which  exists  in  Kansas  and  Missouri,  and  presenting  the 
basis  for  the  great  smelting  industry  which  has  been  developed.  The  lowest 
bed  of  the  Muschelkalk  series  is  a  blue  limestone  known  as  the  Sohlenkalk- 
stein, which  forms  the  lower  limit  of  the  ore  deposits.  Overlying  the  Sohl- 
cnkalkstein  are  dolomites,  which  carry  the  ore. 

The  chief  mineral  district  lies  between  the  towns  of  Scharley,  Brzoso- 
witz,  Kamin,  Baingow,  Antonienhof,  Beuthen,  Miechowitz  and  Stadt  Dom- 
browa.  The  situation  of  those  places  and  the  trends  of  the  mineral  zones 
are  shown  on  the  accompanying  map,  from  which  it  will  be  observed  that  the 
ore  occurs  in  channels  or  troughs  having  a  general  east  and  west  course. 

The  ore  is  found  at  two  horizons,  an  upper  characterized  by  galena  and 
oxidized  zinc  ore  and  a  lower  characterized  by  blende  and  marcasite.  The 
latter  appears  as  an  extensive  bed  of  dolomite  strongly  mineralized  with 
blende  and  marcasite,  and  to  some  extent  with  galena,  sometimes  attaining 
a  thickness  of  15  m.  and  lying  at  depths  of  64  to  115  m.  below  the  surface. 
It  rests  sometimes  directly  on  the  Sohlenkalkstein  and  sometimes  on  a  sheet 
of  dark  gray  dolomite,  known  as  the  Blendedolomit,  1  to  1-5  m.  thick  which 
intervenes  between  it  and  the  Sohlenkalkstein.  The  beds  of  ore  are  exten- 
sive and  persistent  and  the  formation  is  so  regular  that  the  Sohlenkalkstein 
is  an  infallible  guide  in  exploring  for  them.  They  lie  nearly  flat  and  the  drill 
has  been  largely  employed  in  prospecting  the  country.  Overlying  the  ore 
is  a  bed  of  brown  dolomite,  through  which  the  ore  rises  completely  when  at 
its  thickest. 

The  upper  or  lead  horizon  lies  12  to  25  m.  above  the  blende.  It  is  dis- 
tinguished especially  by  a  very  persistent  sheet  of  galena  ore  from  0-05  to 
0-30  m.  thick  lying  between  beds  of  light  colored  dolomite,  high  in  lime. 
This  sheet  of  galena  is  generally  underlain  by  red  calamine  in  stringers, 
masses  and  beds,  which  are  sometimes  powerful  enough  to  give  the  deposit 
an  aggregate  thickness  of  2  m.  The  upper  deposit  is  above  the  water  level 
of  the  district  and  has  been  subject  to  oxidation  and  secondary  mineraliza- 
tion; the  lower  is  below  the  water  level  and  generally  presents  unaltered 
sulphide  ore,  the  only  exception  being  at  the  edges  of  the  troughs  or  basins, 
where  the  two  horizons  frequently  unite ;  at  such  places  ore  bodies  of  great 
thickness  are  apt  to  be  found. 

Deposits  of  calamine  in  the  form  of  nests  and  stock-works,  pipes  and 
sheets  are  also  found  in  the  dolomite,  sometimes  lying  in  or  between  beds  of 
residual  clay.  There  is  no  regularity  in  the  deposits  of  this  class,  and 
being  scattered  through  the  entire  dolomite  formation  of  the  Muschelkalk, 
prospecting  for  them  is  more  difficult  than  for  the  regularly  lying  beds 


OCCURRENCE   OF   2INC    ORE   IN    EUROPE,   AFRICA    AND    AUSTRALIA.       217 

(Flotze)  of  blende.  These  deposits  of  calamine,  which  were  the  first  to  be 
worked  in  the  district,  are  now  approaching  exhaustion.  The  deposits  of 
blende  in  the  Beuthen-Scharley  basin,  to  which  attention  was  first  directed 
in  the  decade  1860-1870,  are  so  extensive,  however,  that  it  must  be  a  long 
time  before  they  are  worked  out. 

Kinds  of  Ore. — The  calamine  of  Upper  Silesia  is  chiefly  smithsonite;  to  a 
less  extent  hemimorphite,  which  mineral  is  rather  characteristic  of  the  lower 
levels.  Near  the  Sohlenkalkstein  the  ore  is  generally  white  calamine 
(chiefly  silicate)  ;  higher  in  the  dolomite  it  is  red  calamine  (chiefly  smith- 
sonite). Sometimes  both  kinds  occur  in  the  same  deposit,  as  in  the  Elisa- 
beth mine,  where  the  ore  body  showed  white  calamine  on  the  foot  wall  of 
Sohlenkalkstein  and  red  calamine  against  the  hanging  wall  of  dolomite. 
The  red  calamine  is  rather  ferruginous  and  frequently  cadmium  bearing. 
The  blende  of  the  great  bed  is  of  cryptocrystalline  character  and  dark  brown 
to  black  in  color.  It  is  apt  to  contain  both  cadmium  and  arsenic.  Mar- 
casite  is  generally  associated  with  it,  especially  in  the  upper  parts  of  the 
deposit,  and  sometimes  next  to  the  Sohlenkalkstein.  Pyrite  is  rather  rare, 
but  galena  is  of  frequent  occurrence,  appearing  in  the  blende  deposit  in  the 
form  of  stringers,  seams  and  irregular  bunches. 

The  zinc  ore  of  Upper  Silesia,  especially  the  calamine,  is  of  low  grade, 
or  rather  it  should  be  said  the  smelting  and  other  conditions  permit  it  to  be 
sent  to  the  reduction  works  in  the  form  of  low  grade  ore.  A  part  of  the 
product  of  the  mines  is  dressed,  certain  of  the  works  being  highly  efficient 
types  of  modern  design;  a  large  part  is  shipped  as  hand-sorted  lump  ore. 
Calamine  as  low  in  grade  as  8%  Zn  is  marketable,  but  ore  of  lower  tenor 
must  be  dressed.  The  rich  white  calamine  in  lumps  assays  43  to  45%  Zn; 
red  calamine  28  to  35%  Zn.  Concentrated  calamine  assays  about  29  to 
30%  Zn.  The  crude  sulphide  ore  which  goes  to  the  dressing  works  assays 
about  10%  Zn.  At  the  Neuhof  mill  ore  assaying  10  to  11%  Zn  is  concen- 
trated in  the  ratio  5:1,  yielding  a  product  assaying  33%  Zn  (showing  a 
saving  of  66%).  At  the  Neue  Helene  blende-mill  (a  highly  elaborated 
plant)  the  blende  concentrate  assays  37  to  40%  Zn.  An  average  for  the 
district  is  perhaps  in  the  neighborhood  of  33  to  35%.  The  purest  blende  ore 
in  lump  form  assays  55  to  60%  Zn;  the  average  is  40  to  45%  Zn.  Blende 
as  low  as  18%  Zn  is  marketable.  Nearly  all  the  Silesian  zinc  ore  contains 
some  lead,  the  best  blende  concentrates  having  about  1%,  other  grades  2% 
or  more.  (As  in  the  Joplin  district  a  considerable  part  of  the  lead  in  the 
crude  ore  is  separated  as  a  galena  concentrate,  assaying  70%  Pb).  Con- 
centrated blende  from  the  Neue  Helene  mill,  in  1893,  had  the  following 
composition:  41-23%  Zn ;  245%  Pb;  5-35%  Fe;  3-24  Al,0a;  1-43%  SiO,; 


218 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


13-6396  C02;  0-33%  S03;  2046%  S;  3-52%  MgO;  8-65%  CaO;  total, 
100-29%.  Concentrated  calamine  from  the  same  mill  assayed:  27-32% 
Zn;  5-35%  S;  0-23%  S03;  6-62%  CaO;  23-02%  C02;  37469$,  undeter- 
mined (oxygen,  silica,  alumina,  iron,  magnesia,  etc.).  Other  analyses  of 
Silesian  zinc  ores  are  given  in  the  following  tables,  which  are  compiled  from 
data  in  Verdichtung  der  Metallddmpfe  in  Zinlchutten,  by  Doctor  Victor 
Steger,  and  Das  Cadmium,  sein  Vorkommen,  seine  Darstellung  und  Ver- 
wendung,  by  Edmund  Jensch. 

Besides  the  zinc  ores  proper  the  iron  ore  of  Upper  Silesia  frequently  con- 
tains zinc,  some  of  which  is  recovered  in  the  scaffolds  and  dust  from  the  blast 
furnaces  and  is  sold  to  the  zinc  smelters;  some  analyses  of  those  products 
are  given  herewith,  together  with  those  of  the  iron  ores  from  which  they 
are  obtained. 

The  footnotes  to  which  the  reference  letters  in  these  tables  pertain  will  be 
found  on  p.  219. 

ANALYSES  OF  CALAMINE. 


No. 

Mine 

Variety 

ZnO 

% 

Ff3 

CaO 

% 

SiO2 

% 

C02 

% 

T 

Ref. 

II 
III 

IV 

Neue  Helene  
Karl  Gustav     . 

Red 

White 

40-46 
39-05 
15-94 
11  '13 

12-08 
12-41 
15-79 
6  '77 

5'23 
9-17 
20-73 
18  '24 

3-91 
4-33 
9-79 
4'71 

4-04 
5-74 
1-83 
9*87 

25-70 
24-66 
33-08 
30  "09 

8-29 
4-35 
2-72 

a 
a 
a 
b 

v 

14  '96 

5  '80 

17-30 

4'47 

12*53 

25  '63 

b 

No. 

Mine 

Variety 

-T° 

PbO 

% 

MnO 

% 

SO3 

% 

Na2O 
K2O 

% 

Total 

% 

Ref. 

I 

Neue  Helene  . 

Red 

99-71 

a 

H 

99  '71 

ft 

III 

it             11 

•< 

99-87 

a 

IV 

Karl  Gustav. 

White 

14'90 

roe 

nil 

0*58 

2  -38 

99-77 

b 

V 

16-17 

0*72 

0-04 

0'44 

1'63 

99-69 

b 

Mine 

Variety. 

Product 

Total 
Zn 

% 

Zn  com- 
bined with 
Si02  % 

Pb 

% 

Fe 

% 

Ref. 

Neuhof  

Red 

Klaubgalmei 
Setzgalmei 

14-92 
18'20 

4-64 
5*12 

0-84 
1*20 

18-50 
12'11 

5 

" 

Grabengalmei 
Lagergalmei 

9-94 
9'60 

3*88 
3*50 

1-54 
0*96 

9-88 
19*12 

c 
c 

» 

11-33 

2-92 

1-76 

29'SO 

c 

Rokoko  '.'.'.    '.    '. 
Hugo  

White 

•• 

11-22 
11-96 
15-30 
13*16 

4-12 
3-15 
2*40 
4  '24 

1*10 
2*30 
0-36 
0*92 

24-16 
13-20 
5-84 
8  '65 

c 
c 
c 

Redlichkeit   .    .  . 

H 

» 

17-52 
12-34 

7*10 
4-00 

0-50 

0-72 

3-15 
9-86 

c 
c 

OCCURRENCES    OF    ZINC    ORE    IN    EUROPE.,    AFRICA   AND   AUSTRALIA.      219 


ANALYSES  OP  BLENDE. 


Mine 

Product 

Zn 

% 

Pb 

% 

Fe 

% 

S 
% 

A12O3 
% 

CaCO3 

% 

MgC03 

% 

Total 
% 

Refer- 
ence 

Neuhof. 

32  50 
33  25 
32  20 
34  '  35 
30  54 
25-20 
29-80 
37-08 
28  50 

2-18 
•86 
94 
•18 
•50 
•86 
92 
•88 
•84 

9-54 
15-15 
17-64 
9'62 
25-42 
24-16 
21-50 
4-64 
13-95 

26-44 
33-29 
34-50 
27-78 
40-12 
39-16 
37-54 
24-62 
28-42 

2  84 
0  64 
0-25 
3-15 

16  25 
9  45 
8-45 
12-65 

10-20 
6-25 
5  75 
9'40 

99  95 
99-89 
100-73 
99  13 

c 
c 
c 
c 
c 
c 
c 
c 
c 

Unknown.  .  .  •< 
Aufschluss.  .  .  . 

St'ickbende.  .  .  . 
Erdblende  
Schliechblende  . 
Grobkorn  
Feinkorn  

Schliechblende. 
Erdblende  
Schlammblende. 

ANALYSES  OF  IRON  ORE. 


Mine 

Fe2O8 

MnO 

PbS 

ZnO 

CaO 

MgO 

P205 

d  Vola- 

elnsol. 

Total 

% 

% 

% 

% 

% 

% 

% 

tile  % 

% 

% 

Redlichkeit;  Reden  shaft  . 

61-60 

2'05 

1-96 

3'27 

0-43 

0  15 

0-28 

13  15 

16-10 

99-49 

Silva  shaft   .  . 

62-90 

2-50 

2'07 

3'17 

0'40 

0-06 

0'22 

11'95 

16-60 

99  37 

Unschuld;  Shaft  No.  18..  . 

58-80 

2  60 

1-92 

3'93 

0-45 

0-09 

0-33 

9'80 

22-00 

99  22 

"     No.  29.  . 

72-65 

1-20 

0\S1 

2'70 

0'25 

0'20 

0-41 

11-20 

10-15 

99-57 

Georgenberg  

63-20 

6-60 

1-785 

0-244 

0-973 

0'231 

10-50 

15-15 

98-683 

BY-PRODUCTS  FROM  SMELTING  IRON  ORE  OF  THE  ABOVE  CHARACTER. 


No. 

Class 

ZnO% 

PbO% 

FeO% 

Fe2O3 

MnO% 

s% 

S08% 

Ref. 

I 

Fluedust 

28-22 

8'72 

22-96 

tr. 

2  58 

0'52 

0'49 

b 

II 
III 
IV 
V 
VI 

Zinkbrocken  (Ofenbruch)  
Dust  from  gas  purifiers  
'     scrubbers  (waschkasten)  .  . 
Wall  accretion  .  .  . 

21'37 
59-42 
26  '68 
13-46 
72  '67 

6'55 
3-93 
4-50 
1'32 
3'41 

26-60 
14-82 
25-96 
30-41 

nil 
1-06 
nil 
nil 
1'26 

3  58 
4  17 
2-20 
7  46 

0-26 
0-12 
0'42 
0'19 

0'70 
0-38 
0-69 
0-44 

b 
b 
b 
b 
b 

VII 

27  '94 

4'62 

j  5  "06 

0.27 

• 

b 

No. 

Class 

Cl 

% 

CaO 

% 

C 

% 

M«O 

% 

A1208 

% 

SiOo 

% 

P205 

% 

Total 

% 

Ref. 

I 
II 
III 
IV 
V 
VI 
VII 

Fluedust  

0.02 
0.07 

tr. 
nil 
O'lO 
0-21 
0-14 

11-68 
13  79 
2-02 
14  28 
20-64 
00'22 
01-38 

"6:08 
0'04 

0-11 

0-30 
0-62 
1-26 
0'84 
0  66 
h  3  -37 
h  5  '40 

23  64 
25'98 
12  34 
23  '62 
25-02 
il8'64 
t55'10 



o-ie 

0  25 
0  21 

99-13 
99  '52 
99-86 
99  69 
100-06 
99-57 
100-17 

b 

b 
b 
b 
b 
b 
b 

Zinkbrocken  (Ofenbruch)  

Dust  from  gas  purifiers  
"     scrubbers  (waschkasten) 
Wall  accretion  

a,  A.  Lindner ;  1),  E.  Jensen ;  c,  authority  not  mentioned ;  d,  carbonic  acid  and  chemically 
combined  water ;  e,  clay  and  sand ;  f,  partly  in  metallic  form ;  g,  as  graphite ;  h,  soluble ; 
i,  firebrick;  ;,  includes  both  FeO  and  Fe2O3.  These  foot-notes  refer  to  all  of  the  above 
tables  of  analyses. 

Mining  Conditions. — In  considering  the  mining  conditions  in  Upper 
Silesia  it  is  necessary  to  remark  that  the  more  part  of  the  mineral  rights 
now  belong  to  tho  comparatively  small  number  of  corporations  and  great 


220  P11ODUCT10X    AND    1'UOPEIiTlKS    OF    ZiAC. 

capitalists  who  own  and  operate  the  smelting  works.  The  portion  of  the 
ore  production  made  by  other  individuals  is  relatively  small.  The  mines 
and  works  can  thus  be  operated  on  a  systematic  policy  to  secure  the  best 
result  and  there  are  few  conflicting  interests.  The  mining  is  conducted  on 
an  extensive  scale,  with  large  and  permanent  works.  In  1893  I  visited  the 
Neue  Helene  mine  (opened  in  1876,  since  which  time  it  has  been  one  of  the 
largest  producers  of  the  district)  and  entered  it  through  a  circular,  brick- 
lined  shaft,  about  4  m.  in  diameter  and  103  m.  deep,  from  the  bottom  of 
which  led  off  a  main  working  gallery,  3  m.  wide,  2  m.  high  and  1,000  m., 
more  or  less,  in  length,  with  brick  walls  the  entire  distance  and  roof  of 
heavy  plank  resting  on  iron  beams — a  rather  magnificent  outlay,  but  one 
that  indicated  confidence  in  the  permanence  of  the  ore  body. 

Westphalia. — The  chief  deposits  of  zinc  ore  in  Westphalia  exist  at  Iser- 
lohn  and  Brilon.  At  Iserlohn  calamine  and  blende  are  found  in  irregular 
pockets,  sometimes  connected,  at  the  contact  between  Eifel  limestone  and 
the  underlying  Lenne  shale,  both  of  Devonian  age;  also  in  crevices  which 
traverse  the  limestone  in  a  network.  The  ore  occurs  with  residual  clays 
and  sands  and  has  some  galena  intermixed.  The  deposits  at  Brilon  are  of 
similar  character,  but  much  of  the  ore  is  found  in  irregular  crevices  in  the 
limestone  and  is  associated  with  pyrite. 

GREAT  BRITAIN  :  England. — Zinc  ore  is  found  in  connection  with  lead  ore 
in  the  North  of  England,  counties  of  Northumberland,  Cumberland,  West- 
moreland, Durham  and  Yorkshire,  in  which  region  the  formation  is  made  up 
of  thick  beds  of  limestone  of  Lower  Carboniferous  age,  alternating  with 
sandstones  and  shales.  The  ores  are  associated  chiefly  with  the  limestones, 
which  are  traversed  by  a  great  number  of  veins  striking  in  various  direc- 
tions. The  so-called  "rake  veins"  running  diagonally  across  the  strata  are 
the  most  productive.  They  have  a  zig-zag  cross-section,  somewhat  like  that 
of  a  flight  of  steps,  dipping  nearly  vertically  (pitches)  and  stretching  off 
horizontally  along  the  strata  (flats),  then  dipping  vertically  again,  and  so 
on.  The  flats  are  often  particularly  rich.  The  veins  are  usually  1  to  4  ft. 
thick,  but  sometimes  attain  17  ft.  Pipe  veins  are  also  known.  The  zinc 
ore  of  this  region  is  blende.  The  mines  at  Nenthead  in  Cumberland  are 
now  being  exploited  on  a  large  scale  by  the  Societe  Anonyme  de  la  Vieille 
Montagne,  which  acquired  them  a  few  years  ago. 

Zinc  ore  is  also  produced  in  Cornwall,  the  principal  mines  being  north 
of  Truro,  in  the  western  part  of  the  County,  and  near  Liskeard  in  the  east- 
ern part,  where  veins  mineralized  with  blende  and  galena  traverse  Devoniai 
clay  slates.     In  the  Isle  of  Man  lodes  intersecting  Cambro-Silurian  slat( 
and  grits  and  fold  spathic  rock?  afford  blonde  and  sralena.     The  Foxdale  lod< 


OCCURRENCES    OF    ZINC    ORE    IN    EUROPE,    AFRICA   AND   AUSTRALIA.      221 

has  been  worked  for  a  distance  of  four  miles  on  its  strike  and  has  been 
found  to  attain  a  thickness  as  great  as  40  ft.  The  Foxdale  mine,  which  is 
situated  at  Foxdale,  belongs  to  the  Isle  of  Man  Mining  Co.;  the  Great 
Laxey  mine  at  Laxey  Glen  is  operated  by  the  Great  Laxey  Mining  Co. 

Wales. — Zinc  ore  is  mined  at  several  places  in  Wales,  but  the  most  im- 
portant producers  are  situated  in  Flintshire  and  Denbighshire,  where  the 
country  rock  is  Lower  Carboniferous  limestone  overlain  by  the  Millstone 
Grit  and  the  Coal  Measures.  The  geological  structure  and  ore  deposits  are 
both  similar  to  those  of  the  North  of  England,  whence  the  limestone  beds 
dip  westward  under  the  Coal  Measures,  Permian  and  New  Bed  Sandstone, 
rising  again  in  Flintshire  and  Denbighshire.  The  formation  is  traversed  by 
parallel  lodes,  which  are  mineralized  in  the  grit  and  limestone  and  are 
barren  in  the  Coal  Measures,  where  they  are  represented  only  by  a  fault 
fissure.  The  ore  deposits  occur  normally  as  crevice-filling  veins,  but  in  the 
limesone  they  occur  also  as  pipes  and  in  caverns,  and  as  flats,  which  form 
nt  the  contact  of  the  limestone  and  sandstone.  The  ore  is  blende,  associated 
with  galena,  occurring  largely  with  a  clay  gangue.  The  mineral  zone  runs 
from  Llangollen  on  the  south  to  Flint,  Holy  well  and  Prestatyn  on  the  north. 
The  Minera  and  Xcw  Mincra  at  Wrexham  and  the  Holkyn  at  Holy  well  are 
the  principal  producing  mines. 

In  Montgomeryshire  lodes  cutting  a  strongly  folded  formation  of  Cam- 
brian-Silurian beds,  comprising  slates,  shales  and  sandstones,  are  worked. 
The  ore  is  blende  and  galena  occurring  in  pipes  and  lenses  in  the  vein  fill- 
ing. In  the  most  important  mining  district,  the  Van  district,  the  lode  is  12 
to  80.  ft.  wide,  filled  with  country  rock  and  clay  and  traversed  by  seams  of 
calcite,  barite  and  quartz,  the  metalliferous  minerals  occurring  in  bunches 
connected  by  stringers.  In  Cardiganshire  there  are  similar  deposits;  also 
in  the  English  County  of  Salop  (Shropshire),  which  adjoins  Montgomery- 
shire on  the  east,  the  most  important  mines  being  at  Minsterley. 

GREECE. — The  large  production  of  zinc  ore  in  this  Kingdom  is  derived 
chiefly  from  the  ancient  mines  at  Laurium,  which  are  thought  to  have  been 
worked  for  lead  and  silver  as  early  as  1200  B.  C.,  and  are  known  certainly 
to  have  been  worked  on  a  large  scale  as  early  as  600  B.  C.  The  magnitude 
of  the  ancient  workings  is  testified  by  the  statement  of  M.  Andre  Cordelia, 
director-general  of  the  Societe  des  Usines  du  Laurium,  that  in  1892  his  com- 
pany had  105,000,000  metric  tons  of  refuse  ore,  assaying  4  to  8%  Pb  and 
1,000  to  1,300  g.  of  silver  per  ton  of  lead,  left  by  the  former  miners,  while 
there  was  about  2,500,000  tons  of  old  slag  containing  10-5%  Pb,  which  did 
not  represent  the  entire  production,  however,  inasmuch  as  large  quantities 


222  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

of  the  skig  made  before  the  Christian  era  were  dumped  into  the  sea.1  In 
1860,  after  17  centuries  of  neglect,2  the  mines  were  reopened  by  a  French 
company,  which  had  obtained  from  the  Grecian  government  a  concession 
for  their  exploitation.  The  Societe  des  Usines  du  Laurium,  successor  to  the 
original  company,  and  the  Compagnie  Franchise  des  Mines  du  Laurium  are 
the  chief  operators  at  Laurium  at  the  present  time.3 

The  country  rock  at  Laurium  consists  of  alternate  formations  of  limestone 
and  mica  schist  (probably  of  Silurian  age)  varying  in  thickness  from  200 
to  300  ft.  and  aggregating  about  1,200  ft.  The  ore  occurs  in  lenses  and 
pockets  at  the  contacts  of  the  lower  formation  of  schist  with  the  underlying 
and  overlying  limestone ;  also  in  funnel  shape  pockets  penetrating  the  lime- 
stones. Crevices  which  cut  the  schists  contain  ore  occasionally  and  irregu- 
larly. The  bedded  deposits  are  from  1-5  to  40  ft.  in  thickness.  In  the 
Camaresa  district  of  Laurium  they  are  developed  over  an  area  of  more  than 
two  square  miles. 

The  ores  are  galena  and  blende,  with  pyrite  and  chalcopyrite  intermixed, 
and  cerussite  and  smithsonite,  the  gangue  being  largely  carbonate  of  iron 
and  ocher.  Those  of  the  upper  contact  are  chiefly  smithsonite  and  are  less 
rich  than  the  lower.  On  the  lower  contact  the  galena  occurs  frequently 
as  a  central  band  in  the  deposit,  separated  from  smithsonite  on  both  sides 
by  a  variable  thickness  of  ocher.  Blende  is  found  chiefly  in  the  lower 
horizon.  In  the  case  of  the  Laurium  ore  deposits  Posepny  considers  it 
doubtful  if  the  smithsonite  was  derived  as  a  secondary  product  from  the 
blende. 

The  ancient  Greeks  had  no  use  for  zinc  ore  and  those  deposits  remained 
untouched  until  the  French  companies  undertook  operations.  It  has  been 
the  Compagnie  Frangaise  des  Mines  du  Laurium  which  has  concerned  itself 
especially  in  zinc  mining.  The  ores  got  at  first  were  high  grade,  assaying 
60%  Zn  after  calcination  (smithsonite  is  referred  to)  and  of  excellent  qual- 
ity. During  the  decade  1890-1900,  however,  most  of  the  high  grade  ore 
appeared  to  have  been  won,  while  the  grade  of  the  smithsonite  produced  ran 
down  to  about  40%  Zn  after  calcination,  and  it  was  much  more  ferruginous 
in  character.  In  1898  new  ore  bodies  were- opened  and  production  increased 
again.  From  1875  to  the  end  of  1893  Laurium  exported  555,000  metric 
tons  of  calcined  calamine.  The  production  since  1893  is  given  in  Chapter  IY. 

Elsewhere  in  Greece  there  -is  a  small  production  of  zinc  ore  from  the  Island 

1  A.  Cordelia,  The  Mining  and  Metallurgl-  obtained  from  the  deposits  at  Laurium  over 
cal  Industries  of  Laurium,  prepared  for  the  2,000,000  tons  of  lead  and  270,000,000  oz. 
Columbian  Exposition  at  Chicago  in  1803.  of  silver. 

2  It    has   been    estimated   from    the   accu-  3  Extensive  operations  by  the  French  com- 
mulationa  of  slag  that  the  ancient  miners  panies  did  not  begin  until  1876. 


OCCURRENCES    OF    ZINC    ORE    IN    EUROPE,    AFRICA   AND   AUblRALIA.      223 

of  Antiparos.  At  Mt.  Hymettus  on  the  mainland  zinc  ore  is  found  in 
limestone. 

ITALY. — The  zinc  mines  of  this  Kingdom,  which  are  at  present  the  most 
productive  in  Europe  after  those  of  Germany,  are  situated  chiefly  in  Sar- 
dinia. Less  important  mines  are  worked  in  Lombardy,  Piedmont  and 
Tuscany. 

Sardinia. — The  richest  mines  in  Sardinia  are  situated  in  the  Iglesias  dis- 
trict in  the  southwestern  corner  of  the  island,  where  both  lead  ore  and  zinc 
ore  are  found.  Mining  was  carried  on  there  by  the  Romans  and  likely  by 
the  Carthaginians  and  Phoenicians  before  them.  The  mines  surround 
Iglesias  to  the  south  and  west  and  extend  about  15  miles  to  the  north.  The 
country  is  composed  of  a  central  mass  of  granite  surrounded  by  Silurian 
schists  and  graywackes,  Cambrian  grits,  quartzites  and  schists  and  a  "metal- 
liferous" limestone  or  dolomite,  which  is  probably  of  Silurian  age.  De- 
posits of  ore  occur  in  all  of  those  rocks,  but  chiefly  along  the  contacts  of  the 
limestones  and  schists;  they  are  found  also  in  crevices  in  the  limestone 
and  along  the  contacts  between  two  different  limestones.  The  lead  ore 
and  zinc  ore  are  intimately  associated,  but  the  proportion  of  blende  increases 
with  depth.  Large  deposits  of  smithsonite  and  hemimorphite  are  found 
near  the  surface. 

The  Malfidano  mines,  situated  about  eight  miles  northwest  of  Iglesias, 
are  among  the  largest  producers  of  zinc  ore.  Calamine  is  found  there  inter- 
stratified  with  limestone  and  sometimes  in  alternating  beds.  The  ore  carries 
a  small  quantity  of  lead.  As  sent  to  the  dressing  works  it  assays  about 
15%  Zn.  It  is  concentrated  in  the  ratio  4-5  :1,  yielding  a  product  which  assays 
about  35%  Zn.  (a  saving  of  about  52%  of  the  zinc  in  the  crude  ore).  Lump 
ore  is  also  produced.  All  the  ore  is  calcined  at  the  mines  before  shipment. 
The  average  of  25,000  tons  exported  to  Antwerp,  about  1892-1893,  was 
5440%  Zn;  6-00%  Pb;  13-75%  0;  6-80%  Fe203+Al208;  6.60% 
CaO+MgO;  940%  Si02;  2-80%  H20+C02;  total  99-75%.  The  mines 
are  operated  by  the  Societe  des  Mines  de  Malfidano,  which  since  1894  has 
had  smelting  works  of  its  own  in  France. 

At  Caitas,  near  Malfidano,  calamine  occurs  in  conical  or  columnar  bodies 
in  limestone  on  either  side  of  a  great  zone  of  brecciation,  100  ft.  wide, 
which  traverses  the  country  rock;  with  depth,  blende  and  some  galena  are 
found. 

The  Monteponi  mines.,  about  one  mile  southwest  of  Iglesias,  are  the  oldest 
in  the  district,  having  been  worked  successively  by  the  Carthaginians, 
Romans  and  Spaniards.  They  produce  both  lead  and  zinc  ores,  which  occur 
in  separate  deposits  and  at  different  horizons.  The  zinc  ore  occurs  in 


224 


PltODUCTIOX    AND    FKOPEUTIKS    OP    ZINC. 


crevices  and  brecciated  masses  in  limestone.  It  assays  about  33%  Zn  and 
contains  much  iron  oxide,  which  is  separated  by  magnetic  concentration 
(vide  Chapter  XI).  Some  cerussite  is  mixed  with  the  ore. 

In  1893  a  dressing  works  capable  of  treating  250  tons  of  ore  per  day  was 
erected  at  Monteponi  to  work  an  accumulation  of  ore,  estimated  to  amount 
to  800,000  tons,  and  to  contain  13  to  18%  Zn  and  1%  Pb,  which  had 
previously  been  considered  of  too  low  grade  to  work.  This  ore  was  a 
mixture  of  smithsonite,  hemimorphite,  blende  and  galena,  with  a  gangue  of 
siderite,  feldspar  and  chalk.  It  yielded  about  13%  of  concentrate.1 

The  Montevecchio  mine,  which  is  exploited  chiefly  for  lead,  is  opened  on 
a  huge  lode,  which  traverses  Silurian  schist  almost  parallel  to  the  contact  of 
the  schist  against  the  granite.  The  lode  has  been  traced  nearly  six  miles 
along  its  outcrop  and  is  75  to  100  ft.  thick.  The  ore  which  is  galena,  mixed 
with  blende,  pyrite,  chalcopyrite,  siderite,  barite  and  quartz,  occurs  as  veins 
along  the  hanging  and  foot-walls  and  also  as  lenses  in  the  interior  of  the 
filling  of  the  lode.  The  proportion  of  blende  increases  with  depth. 

Other  Mines. — The  San  Giovanni  mines,  two  miles  southwest  of  Iglesias, 
have  irregular  lodes,  standing  nearly  vertical,  in  limestone,  which  contain 
argentiferous  galena  in  a  gangue  of  quartz,  barite,  limestone  and  clay  and 
some  blende  in  columnar  masses  or  zones.  The  Malagalzetta  mines,  a  few 
miles  north  of  Iglesias  have  shallow  pockets  of  zinc  ore  in  limestone,  near 
the  surface.  At  Nebida,  five  miles  west  of  Iglesias,  there  are  great  chimneys 
of  calamine,  sometimes  as  much  as  60  ft.  in  diameter  and  extending  to 
depths  of  600  ft.,  in  limestone.  Veins  of  galena  and  calamine  are  also 
worked,  the  wall  rock  being  much  mineralized  by  the  zinc  ore. 

Composition  of  Sardinian  Ore. — The  following  analyses  of  calcined 
calamine  show  approximately  the  composition  of  the  ore  at  present  exported 
from  Sardinia.2 


No. 

%Zn 

%Pb 

%Fe 

%  Ca 

%Mg 

%Si02 

No. 

%Zn 

%Pb 

%Fe 

%Ca 

%Mg 

%8iOi 

1 

50-83 

4'50 

7-63 

5'25 

3'70 

7'  24 

VII  c 

44*70 

1'40 

IS'26 

4-25 

3-60 

9-20 

II 

44-66 

i-oo 

16-16 

2-40 

2-50 

11-50 

VIII 

48-00 

2-28 

12-95 

2-38 

3'64 

8'42 

III 

47-70 

2-73 

13-65 

2'75 

2'25 

10-92 

IX  d 

46-00 

6-00 

aS'50 

4-50 

1-50 

8-00 

IV  6 

49-34 

7-90 

8'22 

2-88 

1-35 

8-30 

X 

51-90 

4-50 

a4'27 

5'75 

0'70 

12-60 

V 

54-30 

0-25 

10-15 

1-75 

1-57 

10'60 

XI 

45'65 

4-20 

a5'25 

13-55 

0-72 

7-85 

VI 

46*80 

12-50 

14'64 

2-92 

2-55 

5-96 

a  Includes    manganese,     b  Also    contained    1*00%  S.     c  Also   contained   0'56%    S. 

tained  0'19%  Cd. 


d  Also    con- 


1  Eng.  and  Min.   Journ..   Sept.   22  and  29,  1894,  pp.  269  and  293. 
«Ad.  Firket.   Annales  des  Mines  de  Belgique,  Vol.  VI,  No.  1. 


OCCriiRENCES    OF    ZI-XC    OKE    IN    EUROPE,    AFRICA   AND   AUSTRALIA.      w-O 

Zinc  Deposits  of  the  Italian  Mainland. — The  Tenda  mine  in  the  Turin 
district  of  Piedmont  has  galena,  with  which  blende  and  pyrite  are  associated. 
At  Argentiera,  near  Aurongo,  in  Lombardy,  zinc  ore  is  found  in  irregular 
deposits  in  Lower  Triassic  shales  and  dolomites.  At  Bottino,  in  Tuscany, , 
blende  occurs  with  argentiferous  galena,  stibnite,  pyrite  and  siderite  in 
quartzose  lodes  in  Paleozoic  schists.  The  English  Crown  Spelter  Co.  oper- 
ates the  Costagels,  Gremme  and  other  mines  in  the  Valle  Seriana,  district  of 
Milan,  Province  of  Bergamo,  whence  it  obtains  about  5,000  tons  per  annum 
of  calamine  assaying  44%  Zn. 

The  zinc  deposits  of  Italy,  aside  from  those  of  Sardinia,  are  of  consider- 
able importance.  Besides  the  ore  which  is  exported  to  Wales,  the  smelters 
of  other  countries  receive  a  good  deal  therefrom.  Thus,  the  Belgian  smelters 
in  1898  imported  59,118  metric  tons  of  ore  from  Sardinia,  and  12,072  tons 
from  elsewhere  in  Italy. 

RUSSIA. — Little  has  been  published  as  to  the  zinc  resources  of  Russia, 
which  it  may  be  inferred  have  not  yet  been  thoroughly  explored.  Only 
the  deposits  of  the  Caucasus  and  Poland  have  been  described,  and  of 
those  only  the  Polish  have  been  exploited,  the  Caucasus  being  still  too 
remote  from  smelting  works. 

Caucasus. — Various  discoveries  of  zinc  ore  have  been  reported  from  this 
region,  especially  in  the  vicinity  of  Alagir,  about  50  versts  from  the 
Wladikawkas  railway,  where  a  Belgian  company  has  operated.  The  occur- 
rence of  blende  near  the  Tschorok  river,  between  Artwin  and  Bortschka,  in 
the  Kutai's  Government,  has  been  mentioned,  and  in  connection  with  galena 
at  Petrowsk.  Near  Tschiatury,  in  the  Kutai's  Government,  blende  assaying 
57-82%  Zn,  has  been  found.1 

Poland. — The  zinc  mines  of  this  Kingdom  have  been  opened  on  deposits 
which  are  an  extension  of  those  of  Upper  Silesia  (q.  v.),  and  are  probably 
similar  to  them  in  most  respects.  Their  exploitation  has  been  confined  so  • 
far  to  near  the  surface  and  has  been  done  mostly  by  open  pits.  In  appear- 
ance the  ores  are  identical  with  Silesian.  The  principal  mining  is  near 
Olkusz  and  Boleslaw,  where  a  great  deal  of  lead  ore  is  said  to  have  been 
got  as  early  as  the  fifteenth  century.  The  Boleslaw  mines  are  owned  by 
the  Sosnowice  Company;  those  near  Olkusz  belong  to  the  Crown,  and  are 
worked  by  lessees.  As  mined  at  present,  the  Polish  zinc  ore  is  of  lower 
grade  than  the  Silesian  (which  is  largely,  if  not  wholly,  due  to  the  facts 
that  but  little  blende  is  mined  and  the  calamine  is  less  extensively  dressed 
by  washing).  There  are  two  zinc  smelters  in  Poland,  namely  the  Sosnowice 
Company,  which  owns  the  Paulina  works  and  Derwis,  Pomeranzow  & 

i  N.  Sokolow  Zap.  imp.  russk.  tech.  ohnchtsch.,  1897,  XXXI,  viii,  p.  7. 


'^26  PRODUCTION    AND   PROPERTIES    OF    ZINC. 

Co.,  who  lease  the  Pod  Bendzinen  works,  which  belong  to  the  Crown.     The 
mines  and  smelteries  are  situated  near  the  town  of  Bendzin. 

SPAIN. — The  large  production  of  zinc  ore  in  Spain  is  derived  chiefly 
from  the  Province  of  Santander,  in  the  north  of  the  Kingdom,  bordering 
on  the  Bay  of  Biscay;  a  smaller  quantity  is  obtained  from  mines  in  the 
vicinity  of  Cartagena,  in  Murcia,  a  province  of  Southeastern  Spain,  abutting 
on  the  Mediterranean  Sea.  Zinc  ore  is  also  found  in  the  Province  of  Teruel, 
in  the  East  of  Spain. 

Murcia. — Zinc  ore  is  found  in  this  Province,  near  Cartagena,  more  or 
less  in  connection  with  the  important  lead  deposits  which  occur  in  that 
region.  The  country  rock  is  Permian  limestone,  overlying  a  formation  of 
schist.  Lenses  of  blende  occur  in  the  latter.  Smithsonite,  associated  with 
siderite,  is  found  along  crevices  and  in  masses  in  the  limestone. 

The  shipments  of  blende  from  Cartagena  in  1901  were  3,750  tons  to 
Great  Britain,  45,900  tons  to  Belgium  and  2,080  tons  to  Germany,  a  total 
of  51,730  tons,  which  was  12,440  tons  more  than  in  1900.  In  1899  the 
shipments  were  about  80,000  tons.  The  shipments  of  calamine  in  1901 
were  197  tons  to  Great  Britain,  2,512  to  Belgium,  and  1,690  to  Germany, 
a  total  of  4,399,  or  about  1,000  tons  more  than  in  1900. 

Santander. — The  zinc  deposits  of  this  Province  occur  in  dolomites  of 
Cretaceous   and    Jurassic   age   and   in    Lower    Carboniferous    limestone 
The    most    productive    are    those    of    Eeocin,    Udias,    and    La    Floric 
Their     ore     consists     chiefly     of     smithsonite     and     hydrozinkite,     t< 
gether  with  hemimorphite  and  blende,  the  last   appearing  in  the  low( 
levels.     The  deposits  assume  chiefly  the  form  of  bed-like  masses  in  Ci 
taceous  and  Jurassic  dolomites,  which  they  have  evidently  replaced;  the 
also  occur  in  crevices  and  as  impregnations.     The  production  of  the  Eeocii 
mines  in  1896  was  24,000  tons  of  calamine  and  810  tons  of  blende;  Udias 
and  La  Florida  produced  7,200  tons  of  calamine.     The  mines  are  controlled 
by  the  Compagnie  Royale  Asturienne  des  Mines,  which  smelts  the  ores  at 
Arnao,  near  Aviles.  in  the  Province  of  Asturias,  and  at  Auby  in  France. 

The  Picos  de  Europa  mines  are  in  disturbed  Carboniferous  limestone. 
The  Andosa  deposits  show  a  series  of  parallel  veins,  a  few  inches  to 
32  ft.  in  width,  in  a  zone  about  a  mile  long  and  half  a  mile  wide.  The  ore 
is  principally  smithsonite.  In  the  Aliva  deposits,  six  miles  further  west,  the 
ore  is  chiefly  blende. 

Teruel. — Valuable  deposits  of  calamine  assaying  49  to  54%  Zn  exist  at 
Linares  in  this  Province,  where  they  were  first  opened  about  1890.  Their 
production  has  not  yet  been  large,  owing  to  the  lack  of  cheap  transportation 


OCCUHUKXCES  OF  ZIXC  ORE  IX  EUROPE,  AFRICA  AND  AUSTRALIA.         227 

facilities,  there  being  no  railway  near,  but  it  is  considered  that  the  mines 
will  be  an  important  source  of  zinc  in  the  future. 

SWEDEX. — Zinc  ore  is  found  in  Sweden  in  the  provinces  of  Orebro,  Kop- 
parberg  and  Nerike,  but  the  mines  of  Ammeberg  in  Nerike,  which  are 
owned  and  operated  by  the  Societe  Anonyme  de  la  Vieille  Montagne,  are 
the  only  ones  of  importance.  Those  mines  are  situated  at  the  northern 
end  of  Lake  Wetter,  about  120  miles  W.S.W.  of  Stockholm,  and  about  eight 
miles  from  Ammeberg,  with  which  place  they  are  connected  by  a  railway. 
The  dressing  works  and  roasting  furnaces  are  at  Ammeberg  and  Johannes- 
borg,  about  three  miles  from  Ammeberg.  The  country  rock  is  schistose 
gneiss  of  Laurentian  age,  folded  and  contorted.  This  rock,  which  is  fine 
grained,  is  in  places  impregnated  with  blende,  pyrite  and  galena,  the  min- 
eralized portions  having  the  form  of  lenses,  which  occupy  a  nearly  vertical 
position  and  conform  to  all  the  undulations  of  the  country  rock.  Their 
average  thickness  is  about  25  ft.,  though  they  sometimes  attain  50  ft.; 
their  length  reaches  hundreds  of  feet  and  in  depth  they  have  been  exploited 
600  ft. 

The  blende  appears  to  have  taken  the  place  of  the  mica  in  the  schist, 
so  the  mineral  has  ordinarily  a  finely  intermixed  gangue  of  quartz  and 
feldspar,  but  there  is  considerable  blende,  which  is  sufficiently  pure  to  be 
separated  by  hand  sorting,  while  a  good  deal  of  worthless  country  rock,  or 
gangue,  can  be  culled  in  the  same  manner.  About  7,000  tons  of  lump 
blende  are  thus  picked  out  annually.  The  ore  which  goes  to  the  dressing 
works  contains  about  20%  Zn  and  under  \%  Pb.  It  is  concentrated  with 
great  care,  the  ore  being  slightly  roasted  previous  to  crushing  and  jigging 
in  order  to  facilitate  removal  of  the  pyrite  (vide  Chapter  XI),  so  that 
the  loss  in  dressing  is  comparatively  low,  amounting  to  only  20  to  21%. 
The  ratio  of  concentration  is  very  low.  however,  inasmuch  as  after  roasting, 
to  which  all  the  ore  is  subjected  at  the  mines  before  shipment,  the  mineral 
assays  only  38%  Zn.  its  tenor  in  Fe203  being  6%.1  The  culled  blende 
raises  the  average  tenor  of  zinc  in  the  ore  shipped  to  42%.  Great  pains  arc 
taken  to  effect  a  good  separation  of  the  galena  in  the  ore  and  the  Amme- 
berg concentrate  ranks  consequently  as  mineral  of  excellent  character  as  to 
purity. 

TURKEY. — According  to  H.  R.  Jastrow,2  zinc  ore  is  found  to  some  extent 
in  Balia,  Province  of  Brussan,  but  the  chief  source  of  supply  is  Karsasu  on 
the  Black  Sea.  Zinc  ore  is  also  found  in  the  neighborhood  of  Smyrna. 
The  total  production  of  the  Empire  approximates  5,000  tons  per  annum. 

1  P.  G.  LIdner.  Trans.  Am   Inst.  Min    Eng.,XXIV,  494. 
'  Eng.  and  Min.  Journ..  May   18,  3901. 


228  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

the  most  part  being  shipped  to  Belgium.     In  1898,  Belgian  smelters  re- 
ceived 3,053  metric  tons  of  ore  from  Turkey. 

ZINC  ORE  DEPOSITS  OF  AFRICA. 

ALGERIA. — Zinc  ore  is  mined  rather  extensively  at  various  places  in  this 
Colony.  The  deposits  of  Sakamody,  Guerrouma  and  R'arbou  are  in  the 
northern  part,  near  the  Little  Atlas  Mountains.  They  occur  in  veins  in 
Cretaceous  marls,  schists  and  limestones,  all  more  or  less  argillaceous.  The 
ore  is  calamine  above  the  water  level  and  blende  below  it,  the  gangue  being 
country  rock  together  with  barite  and  siderite.  Galena  is  apt  to  be  asso- 
ciated with  the  blende.  At  Sakamody  there  is  a  schist  breccia  with  blende 
cementing  the  fragments.  In  the  Department  of  Constantine,  in  the  north- 
eastern corner  of  Algeria,  are  the  Hammam  N'bails  and  Ain  Arko  mines, 
which  are  exploited  by  the  Societe  Anonyme  de  la  Vieille  Montagne.  The 
Oued  Moziz  mine  in  the  Department  of  Oran  yields  both  zinc  and  lead 
ores.  New  explorations  for  zinc  ore  were  undertaken  in  1896  in  the  Djebel 
Belkif,  Commune  de  Morsott,  where  there  are  promising  outcrops  of  cala- 
mine and  galena,  not  far  from  the  Youks  and  Morsott  stations  of  the 
Bone-Guelma  line  of  railway  from  Soukarras  to  Tebessa. 

TUNIS. — Five  calamine  deposits  are  worked  under  concessions  in  this 
Colony,  all  situated  in  the  northern  part.1 

1.  Kanguet  and  Tout  lies  about  30  km.  from  Beja,  on  the  road  from 
Beja  to  the  port  of  Tabarka,  which  at  present  is  only  finished  from  Beja  to 
the  mine.    The  ore  occurs  in  an  irregular  stock-work.    The  mine  is  worked 
open-cast.     The  ore  is  sorted  into  lump  and  fines,  the  former  being  calcined 
in  kilns  with  charcoal.     The  calcined  calamine  is  freighted  by  mule  or 
camel  to  Beja,  and  thence  to  Tunis.     From  Tunis  the  ore  goes  to  Antwerp. 
The  production  is  between  3,000  and  4,000  tons  per  annum. 

2.  The   Sidi-Ahmet  concession,  belonging  to   Compagnie  Eoyale   As- 
turienne  des  Mines,  lies  north  of  the  Sidi-Ahmet  Mountains,  about  40  km. 
from  Beja.     It  contains  at  least  three  deposits,  of  which  the  first  yielded 
about  35,000  tons  of  good  calamine  previous  to  1896.     The  ore  is  hand- 
sorted  and  calcined  in  kilns.     The  annual  production  is  about  3,500  tons 
of  calcined  ore. 

3.  Fedj-el-Adoum  lies  20  km.  southwest  of  Tebursuk,  in  the  highest  part 
of  the  Jouaouda  Mountains,  which  rise  to  an  elevation  of  907  m.     There 
are  three  groups  of  deposits,  of  which  only  one  is  exploited.     This  is  very 
extensive;  in  1896  about  50,000  tons  of  ore  was  estimated  to  be  in  sight. 
The  ore  is  calcined,  after  hand-sorting,  and  is  shipped  via  Tebursuk. 

1  E.  de  Fages,  Glttckauf.  March  27,  1897,   p.  245. 


OCCURRENCES    OF    ZIXC    ORE    IX    EUROPE,    AFRICA   AND   AUSTRALIA.     229 

4.  Zaghouan  lies  about  60  km.  south  of  Tunis,  near  the  village  of  Zag- 
houan.     There  are  two  important  deposits;  in  1897  about  40,000  tons  of 
carbonate  ore,  averaging  40%  Zn,  had  been  proved.     Zinc  silicate  appears 
more  frequently  here  than  in  the  other  localities.     The  mines  are  connected 
by  a  mule-path  and  a  15-km.  tramway  with  the  railway  between  Tunis  and 
Zaghouan.     There  are  three  shaft  furnaces  and  one  reverberatory  at  the 
mines  for  calcining  the  ore.     The  annual  production  is  5,000  tons  of  cal- 
cined ore. 

5.  El  Akhouat  lies  about  32  km.  southwest  of  Tebursuk.     The  ore  is 
carried  in  two-wheel  carts  to  Madjez-el-Bab,  and  thence  by  rail  to  Tunis. 
This  concession  was  only  granted  in  1896,  and  its  production  has  not  yet 
become  important.. 

Zixc  ORE  DEPOSITS  OF  AUSTRALIA,  TASMANIA  AND  NEW  CALEDONIA. 

AUSTRALIA. — The  production  of  zinc  ore  in  Australia  is  confined  to  the 
Broken  Hill  district  of  New  South  Wales,  where  it  is  made  by  the  mechanical 
separation  of  the  blende  of  the  mixed  sulphide  ore  which  exists  there  in  vast 
quantity.  The  ore  deposits  of  Broken  Hill  occur  in  an  immense  lode  in 
primitive,  crystalline  schists,  which  cuts  the  country  rock  at  a  slight  angle 
in  its  dip,  but  agrees  with  it  in  strike.  The  schist  is  for  the  most  part  fine 
grained,  but  is  sometimes  gneissose  in  character  and  at  other  times  is  silici- 
fied  to  a  quartzite;  garnetiferous  sandstone  also  occurs.  The  lode  has  a 
prominent  cap  of  iron  ore  at  the  surface,  which  further  down  passes  into 
ferruginous  quartz,  silver  bearing  kaolin  and  oxidized  silver-lead  ore,  and 
below  the  water  level  changes  to  galena  and  blende.  Included  portions  of 
the  country  rock  are  common  in  the  lode  and  at  one  point  it  is  split  by  the 
schist,  which  has  led  to  the  suggestion  that  the  lode  is  a  "saddle  reef." 
The  thickness  of  the  ore  body  averages  about  60  ft.,  but  in  some  places  it 
has  been  found  100  ft. 

The  sulphide  ore,  which  is  the  only  source  of  zinc  in  these  mines,  is  a 
mixture  of  galena  and  blende,  which  are  so  intimately  commingled  that 
distinct  minerals  are  difficultly  detected  by  the  unaided  eye.  It  assays  10  to 
15  oz.  silver  per  metric  ton,  15  to  20%  Pb  and  20  to  25%  Zn.  The  gangue 
minerals  are  garnet,  rhodonite,  quartz  and  feldspar,  the  garnet  being  espe- 
cially a  constituent  of  the  friable  ore,  which  constitutes  about  20  to  30% 
of  the  whole  production.  The  percentage  of  iron  in  the  ore  is  not  very 
high;  part  of  it  exists  as  sulphide,  the  remainder  as  a  constituent  of  the 
gangue  minerals,  the  same  being  true  of  the  manganese.  Ashcroft  gives 
the  following  analysis  as  representative  of  the  available  ore:  20%  Pb,  20% 


230  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

Zn,  8%  Fe+Mn  (present  as  sulphides),  18%  S,  and  34%  gangue.1  Ac- 
cording to  Green  way,  the  average  grade  of  the  Broken  Hill  ore  is  not  so 
high,  his  estimate  being  14  to  20%  Pb,  10  to  20%  Zn,  and  6  to  16  oz. 
Ag  per  ton.2  The  intimate  association  of  the  constituent  minerals  of  this 
ore  in  which  considerable  proportions  of  both  the  galena  and  the  blende 
occur  as  mere  films  and  specks  in  joints  and  in  fracture  and  cleavage  planes, 
and  the  presence  of  the  garnet  (sp.  gr.  3-5  to  4-3)  and  the  rhodonite  (sp. 
gr.  3-5  to  3-7)  make  it  very  difficult  to  obtain  a  clean  high  grade  zinc  con- 
centrate by  gravity  concentration;  and  the  economical  treatment  of  the 
Broken  Hill  ore,  of  which  upward  of  10,000,000  tons  are  available,3  has 
long  been  a  complex  metallurgical  problem,  of  which  a  satisfactory  solution 
has  not  yet  been  found.4 

The  present  results  obtained  in  the  treatment  of  the  mixed  sulphide  ores 
of  Broken  Hill,  New  South  Wales,  by  wet  dressing  and  smelting  the  con- 
centrates are  shown  in  a  recent  report  of  the  Sulphide  Corporation,  Limited, 
.which  operates  the  Central  mine  at  Broken  Hill,  where  it  has  a  dressing 
works,  the  concentrates  being  smelted  at  works  at  Cockle  Creek.  In  1899 
there  were  treated  201,411  tons  of  ore,  which  produced  40,989  tons  of  lead 
concentrate,  2,338  tons  of  zinc  concentrate,  41,173  tons  of  middlings,  16,125 
tons  of  slimes  and  100,786  tons  of  tailings.  The  recovery  of  lead  in  the 
concentrates  was  70-3%  and  of  silver  about  45%,  the  total  contents  of  the 
ore  treated  having  been  37,277  tons  of  lead  (18-508%),  44,362  tons  of  zinc 
(22-026%),  and  2,510,033  oz.  of  silver  (12-46  oz.  per  ton).  The  cost  of 
mining  and  milling  was  as  follows :  mining,  including  handling  waste  and 
filling,  $2-37  per  ton;  development,  $0-24;  traction,  crushing  and  main- 
tenance, $0-18 ;  dressing,  $0-73 ;  total,  $3-52. 

At  the  Cockle  Creek  smelting  works  there  were  smelted  31,305  tons  of 
lead  concentrate,  2,732  tons  of  Ashcroft  residues,  67  tons  of  dry  ore  from 
the  Central  mine,  1,413  tons  of  purchased  ores,  and  1,041  tons  of  matte  and 
flue  dust,  a  total  of  36,558  tons,  which  yielded  18,596  tons  of  silver-lead, 
containing  946,855  oz.  of  silver  and  1.787  oz.  of  gold:  and  matte  containing 
876  tons  of  lead  and  91,140  oz.  of  silver.  The  total  quantity  of  silver  pro- 
duced was  1,037,995  oz.  The  approximate  averages  were  50-5%  Pb,  28-4 
oz.  silver  and  0-05  oz.  gold  per  ton  of  ore  smelted.  The  total  profit,  before 
deducting  interest  on  the  bonds,  depreciation,  etc.,  was  £131,218. 

1  In  a  paper  entitled  Sulphide  Ore  Treat  « The    direct    smelting    for    zinc    by    the 

ment  by  the  Phoenix  Process,  read  before  the  Picard  &   Snlman   process   of  the  middlings 

Institution  of  Mining  and  Metallurgy,  June  obtained  from   this   ore   by   gravity   concen- 

19,  1901.  tration     has     lately     been     inaugurated    at 

'The  Mineral  Industry,  IX.  745.  Cockle   Creek,   but   the   process   is   still   too 

8  E.  A.  Ashcroft.  Transactions  of  the  In-  new    to    determine    its    commercial    results. 

stitution  of  Mining  and  Metallurgy,  1898.  Vide  Eng.  and  Min.  Journ.,  July  26,  1902. 


OCCURRENCES    OF    ZINC    ORE    IN    EUROPE,    AFRICA   AND   AUSTRALIA.      231 

NEW  CALEDONIA. — At  least  one  large  deposit  of  zinc-lead  sulphide  ore 
is  known  in  the  northern  end  of  this  island,  where  it  occurs  in  a  schistose 
formation.  The  deposit  is  said  to  be  of  rather  large  dimensions.  The 
upper  portion  has  become  thoroughly  oxidized,  losing  at  the  same  time  much 
of  its  zinc  contents  and  becoming  an  ore  of  a  class  suitable  for  lead  smelting. 
A  lead  smelting  plant  was  erected  on  the  seashore  a  few  miles  away  to 
treat  this  ore,  but  has  been  abandoned ;  not,  however,  for  lack  of  ore,  there 
being  a  good  deal  of  carbonate  ore  still  in  sight,  it  is  said,  independent  of 
what  may  yet  be  uncovered.  The  tenor  of  the  ore  in  silver  is  low,  being 
10  to  25  oz.  per  ton.  Beneath  the  oxidized  ore  occur  the  undecomposed 
lead-zinc  sulphides,  which  in  appearance  resemble  those  of  the  Broken  Hill 
district  in  New  South  Wales. 

TASMANIA. — A  large  deposit  of  mixed  sulphide  ore  has  been  opened  in 
the  Roseberry  mine,  belonging  to  the  Tasmanian  Copper  Co.,  on  the  western 
slope  of  Mt.  Black  in  the  County  of  Montague  in  the  West  Coast  district  of 
Tasmania,  about  12  miles  northeast  of  Zeehan  and  18  miles  north  of  the 
Mt.  Lyell  copper  mines.  Roseberry  is  distant  from  the  port  of  Burnie,  on 
Emu  Bay,  72  miles  by  the  line  of  the  Emu  Bay  Railway  Co.  The  country 
rock  in  the  vicinity  of  Rosebery  is  micaceous  schist,  with  interstratified 
sheets  of  limestone,  slate,  sandstone  and  quartzite  and  frequent  intrusions  of 
diorite.  There  are  numerous  large  and  well  defined  mineralized  lodes, 
which  usually  cut  across  the  strike  of  the  stratified  rocks. 

The  Rosebery  lode  is  apparently  a  fissure  vein,  which  has  an  average  dip 
of  about  60°,  and  has  been  traced  on  the  surface  for  upward  of  3,000  ft. 
Its  width  where  opened  underground  is  from  15  to  41  ft.,  averaging  about 
25  ft.  The  ore  is  a  solid  body  of  sulphide,  chiefly  a  laminated  mass  of 
pyrite  and  blende,  in  which  there  occur  irregularly  bands  of  an  intimate 
mixture  of  blende  and  galena  (about  three  parts  blende  to  one  of  galena), 
and  also  bands  of  comparatively  clean  pyrite.  Throughout  the  whole  deposit 
there  is  a  small  quantity  of  chalcopyrite,  with  occasional  small  veins  and 
pockets  of  ore  of  good  grade  in  copper.  At  the  end  of  1899  the  Tasmanian 
Copper  Co.  estimated  that  there  was  upward  of  400,000  tons  (of  2,240  Ib.) 
blocked  out  and  probably  a  great  deal  more  in  the  mine.  The  average 
grade  of  the  ore  was  computed  to  be  0-155  oz.  gold  and  8-625  oz.  silver  per 
ton,  0-77%  Cu,  25%  Zn  and  4-73%  Pb,  and  about  20%  Fe,  the  remainder 
being  sulphur  corresponding  to  the  above  metals,  and  the  gangue  of  silica 
and  alumina,  chiefly  the  former.  The  cost  of  mining  was  estimated  at  12s. 
per  2,240  Ib.,  the  rate  of  wages  in  the  district  being  9s.  per  eight  hours. 
Coal  costs  20s.  per  ton,  plus  an  import  duty  of  4s.  and  coke  44@46s.,  both 
those  supplies  being  obtained  from  New  South  Wales. 


XI. 
MECHANICAL  CONCENTRATION  OF  ZINC  ORES. 

The  Belgian  and  Rhenish  methods  of  zinc  winning,  which  are  the  ones 
generally  in  use  outside  of  Upper  Silesia,  require,  or  at  all  events  give  the 
most  satisfactory  results,  with  a  comparatively  high  grade  ore — i.e.,  one 
that  contains  at  least  40%  Zn,  after  calcination  or  roasting,  and  preferably 
more.  A  roasted  blende  which  assays  50%  Zn  must  have  contained  45% 
Zn  before  roasting  if  10%  in  weight  were  lost  in  that  operation,  and  a 
calcined  calamine  (zinc  carbonate)  of  the  same  tenor  would  have  had  37-5% 
Zn  before  calcination  if  the  loss  in  weight  had  been  25%.  A  sulphide  ore 
assaying  45%  Zn  contains  67%  blende,  even  if  the  latter  bears  no  isomor- 
phous  iron  or  cadmium  sulphide.  There  are  few  blendes  which  are  quite  free 
from  iron  monosulphide  chemically  or  mineralogically  combined  with  the 
zinc,  and  the  foregoing  calculation  shows  the  rather  high  degree  of  purity 
that  is  possessed  by  a  raw  sulphide  ore  assaying  only  45%  Zn.  European 
zinc  smelters  do  not  require  this  grade  to  be  exceeded,  but  in  the  Joplin 
district  of  the  United  States  it  has  become  the  custom  to  produce  blende 
concentrates  assaying  60%  Zn.  These  contain  a  little  galena  and  pyrite 
and  some  monosulphides  of  iron  and  cadmium,  so  that  it  may  be  assumed 
that  an  assay  of  60%  Zn  indicates  a  tenor  of  at  least  92%  of  "mineral,"  the 
remainder  being  chiefly  silica.  It  is  obvious  that  so  high  a  degree  of  con-  . 
centration  cannot  be  effected  mechanically  without  extraordinary  losses  in 
the  tailings  except  in  the  case  of  favorable  kinds  of  ore. 

Objects  and  Limitations  of  Concentration. — The  mechanical  concentra- 
tion or  dressing  of  zinc  ores  is  done  practically  by  manual  selection,  by 
gravity  separation  and  by  magnetic  separation,  two  or  all  three  of  these 
systems  often  being  combined.  In  concentrating  zinc  ores  it  has  to  be 
kept  in  view  not  only  to  enrich  the  ore  by  removal  of  the  gangue,  which  is 
composed  usually  of  light  minerals,  but  also  to  separate  the  heavy  minerals 
which  may  be  injurious  in  the  smelting  process.  For  example,  all  of  the 
lead,  iron  and  manganese  minerals  are  particularly  objectionable  and  ought 
to  be  eliminated  as  completely  as  can  be  done  economically.  Even  when  this 


MECHANICAL    CONCENTRATION    OF   ZINC    ORES.  233 

be  done  blende  ore  is  apt  to  contain  a  large  percentage  of  iron  on  account  of 
monosulphide,  FeS,  combined  isomorphously  with  the  zinc  sulphide;  thus 
the  shining,  black  blende  of  Freiberg,  Saxony,  sometimes  contains  as  much 
as  30%  Fe;  a  specimen  of  similar  appearance  from  Mexico  analyzed  by  me 
gave  10%  Fe.  Cadmium  sulphide  also  occurs  isomorphous  with  zinc 
sulphide,  especially  in  the  case  of  reddish  blendes,  and  similarly  the  carbon- 
ates of  iron  and  cadmium  are  associated  ismorphously  with  zinc  carbonate, 
the  Silesian  ores  almost  invariably  containing  from  0-1  to  0-2%  Cd. 

The  dressing  of  ordinary  zinc  ores,  which  are  apt  to  be  mixtures  of  blende 
and  galena,  with  such  gangue  minerals  as  quartz  and  calcite,  or  calamine 
with  similar  gangue,  does  not  offer  especial  difficulty,  owing  to  the  great 
difference  in  the  specific  gravities  of  the  component  minerals.  The  presence 
of  pyrite,  marcasite,  barite,  or  siderite  complicates  matters  because  those 
minerals  are  of  about  the  same  specific  gravity  as  blende,  smithsonite,  hydro- 
zinkite  and  hemimorphite,  and  in  this  case  magnetic  separation  is  likely  to 
be  necessary  as  an  accessory  process.  The  complex  silver-bearing,  zinc-lead 
sulphide  ores,  like  those  of  the  Eammelsberg  in  the  Lower  Harz  (Ger- 
many), Kokomo  and  Leadville,  Colo.,  Broken  Hill,  N.  S.  W.,  and  else- 
where, cannot  be  separated,  either  by  gravity  or  by  magnetism,  so  as  to 
produce  a  first  class  zinc  ore,  although  recent  progress  in  the  art  of  ore 
dressing,  especially  the  introduction  of  the  improved  shaking  tables,  has 
f enabled  a  marketable  zinc  product  to  be  obtained  from  the  Leadville  ore. 
Magnetic  separation  has  been  applied  with  more  or  less  success  at  Broken 
Hill  for  the  separation  of  the  mixed  sulphide  ore  which  is  mined  there ;  and 
with  quite  satisfactory  results  in  connection  with  the  mixed  ore  of  Lead- 
ville, Colo.  With  calamine  ores  gravity  separation  is  frequently  rendered 
difficult  by  their  earthy  or  drusy  character,  which  prevents  so  successful  a 
removal  of  impurities  of  nearly  the  same  specific  gravity  as  in  the  case  of 
the  denser  and  crystalline  blendes. 

In  general  the  mechanical  concentration  of  zinc  ore  does  not  differ  in 
principle  from  the  practice  with  lead  and  copper  ores  and  with  respect  to 
the  subject  reference  should  be  made  to  the  special  treatises  upon  it.  The 
scope  of  this  work  permits  only  general  suggestions  and  detailed  accounts  of 
a  few  special  processes,  except  that  the  subject  of  hand  sorting,  because  of  its 
importance  and  the  scant  attention  that  is  usually  given  it,  is  treated  rathor 
fully. 

MANUAL  SELECTION  OR  HAND  SORTING. 

When  the  mineral  is  coarsely  mixed  with  the  gangue  it  is  feasible  to 
separate  it  to  a  considerable  extent  by  means  of  hand  sorting.  This  process 


234  PRODUCTION    AND   PROPERTIES    OF    ZINC. 

is  generally  practised  to  a  certain  degree  as  a  part  of  the  mining  of  the  ore, 
in  which  high  grade  ore  may  sometimes  be  broken  out  of  the  lode  separately ; 
sometimes  pieces  of  worthless  waste  can  be  picked  out  of  mixed  ore  and  left 
underground  to  fill  old  stopes,  etc.  As  to  whether  the  hand  sorting  process 
shall  be  carried  further  on  the  surface  depends  on  the  local  conditions, 
especially  the  losses  experienced  in  mechanical  dressing,  the  cost  of  dressing 
and  the  cost  of  sorting,  of  which  the  loss  in  dressing  is  likely  to  be  the  most 
important  consideration.  If  pure  mineral  be  broken/ a  portion  of  it  will 
be  converted  into  fines  (the  percentage  depending  upon  the  brittleness  of 
the  mineral,  the  size  to  which  it  is  broken,  and  the  method  of  breaking)  and 
in  washing  with  water  a  good  deal  of  such  fines  will  escape  settling,  no  mat- 
ter how  perfect  and  painstaking  be  the  process  of  settling.  It  is  therefore 
an  axiom  in  mechanical  dressing  to  avoid  breaking  the  mineral  any  finer 
than  necessary,  and  avoid  breaking  it  at  all  if  that  be  economical.  These 
conditions  are  met  most  completely  by  the  process  of  hand  sorting,  wherein 
two  classes  of  ore  will  usually  be  made :  I,  clean  mineral,  perhaps  divided 
into  (a)  blende  and  (6)  galena;  and  II,  mixed  mineral  and  gangue,  which 
is  sent  to  the  dressing  works.  If  the  cost  of  dressing  be  high  it  is  some- 
times economical  to  sort  out  a  third  class,  III,  clean  gangue,  or  waste, 
thereby  saving  the  expense  of  crushing  and  washing  worthless  material  and 
increasing  the  capacity  of  the  mill.  Under  other  conditions  it  may  be 
cheaper  to  let  the  waste  go  through  the  mill.  This  can  be  determined  only 
by  a  study  of  the  conditions  in  each  particular  case.  It  may  be  remarked, 
however,  that  the  merits  of  hand  sorting  are  seldom  given  in  America  the 
consideration  which  they  deserve,  and  where  practised  the  system  is  rarely 
designed  to  secure  the  best  results. 

METHODS  OF  BREAKING  THE  ORE. — Hand  sorting  of  ore  involves  usually 
two  processes :  I,  breaking ;  II,  selection.  The  breaking  is  done  mechan- 
ically by  jaw  crushers  or  manually  with  the  aid  of  hammers.  The  former 
method  is  the  cheaper,  but  it  produces  the  more  fines ;  while  breaking  with 
hammers  is  not  excessively  costly  if  properly  done,  and  if  the  ore  must  not 
be  broken  to  a  very  small  size.  The  size  to  which  the  ore  must  be  broken 
depends  obviously  on  what  is  required  to  free  the  pieces  of  pure  mineral 
for  the  maximum ;  and  what  can  be  picked  over  economically  for  the  mini- 
mum ;  the  choice  between  the  two  extremes  will  depend  naturally  upon  the 
grade  which  it  is  desirable  to  obtain  for  the  sorted  mineral. 

Proportion  of  Fines  Made. — With  respect  to  the  relative  efficiency  of 
machine-breaking  and  hand-breaking  in  so  far  as  the  proportion  of  fines 
made  is  concerned,  in  default  of  figures  relating  specifically  to  zinc  ore,  I  am 
compelled  to  quote  the  results  of  a  test  on  a  copper  ore  by  Doctor  E.  D. 


MECHANICAL    CONCENTRATION    OF    ZINC    OKLS. 


235 


Peters,  Jr.,  which,  so  far  as  I  am  aware,  is  the  only  reliable  datum  of  this 
nature  on  record.1  The  test  was  made  with  three  different  varieties  of 
sulphide  ore  of  average  hardness,  the  lots  aggregating  2,220  tons,  after  the 
fines  which  they  contained,  as  received  from  the  mine,  had  been  removed 
by  passing  over  a  screen  of  three  meshes  to  the  linear  inch,  the  apertures  of 
the  screen  being  6X6  mm.  One  half  (1,110  tons)  was  broken  by  means  of  a 
7X10-in.  jaw  crusher,  with  corrugated  plates  (which  produce  decidedly 
less  fines  than  smooth  plates)  run  at  240  r.  p.  m.,  with  a  discharge  opening  of 
2-5  in. ;  the  other  half  was  broken  by  experienced  men,  with  proper  ham- 
mers, into  pieces  of  a  similar  maximum  size — i.e.,  2-5  in.  The  products  were 
passed  separately  over  a  3-mesh  screen  (6X6  mm.)  and  the  fines  were 
weighed.  The  results  were  as  follows: 


Character  of  Product. 

Jaw  Crusher. 

Hand  Spalling 

Fine  product  —  below  6  mm  in  diameter. 
Coarse  product  —  bet.  6  mm  and  64  mm.. 
Total 

Tons. 
192-25 
917-75 

i&» 

82-68 

Tons. 
103-34 
1006-66 

A 

90-69 

1110-00 

100-00 

1110-00 

100-00 

Cost  of  Breaking. — With  respect  to  the  relative  cost  of  machine-breaking 
and  hand-breaking  the  advantage  is  decidedly  in  favor  of  the  former.  With 
a  jaw  crusher  capable  of  breaking  200  tons  of  ore  per  10  hours  and  elevator 
and  screen  of  corresponding  capacity  the  cost  will  be  from  7  to  10c.2  per 
ton  (varying  according  to  the  wages  for  labor)  including  power,  labor, 
repairs  and  renewals,  and  amortization  of  plant,  if  the  plant  be  run  at  its 
full  capacity.  The  cost  of  spalling  100  tons  per  10  hours  is  computed  by 
Peters  substantially  as  follows :  One  foreman,  $2*50  per  day ;  14  men  break- 
ing ore,  including  screening  and  loading,  @$1-50  per  day,  $21-00 ;  four  men 
sledging  and  loading,  @$1-50,  $6-00;  five  hammer  handles,  @30c.,  $1-50; 
7  Ib.  steel,  @15c.,  $1-05;  labor  of  smith  in  making  hammers,  one  third  day, 
(o)$3-00,  $1-00:  screens,  forks  and  shovels,  $1-67;  general  repairs,  $0-55; 
total,  $35-27  (=$0-3542  per  ton),  of  which  $29-50  is  for  labor  and  $5-77 
for  material. 

SPALLING. — Such  an  economical  hand-spalling  is  possible  only  when  the 
work  is  properly  conducted.  Attempts  to  sort  ore  with  one  set  of  men,  who 
do  both  the  breaking  and  sorting,  are  likely  to  be  failures,  because  of  the 
costliness  of  the  process.  The  breaking  should  be  done  by  one  gang  and  the 
sorting  by  another.  The  breakers,  or  spallers,  should  stand  up  to  the  work. 

1  Modem  Copper  Smelting,  p.  89. 

1  The  cost  will  be  about  10  cents  when  labor  is  paid  at  the  rate  of  $3  per  day. 


PUODUCTIOX    AND    PUOPEllTIEb    Or    ZINC. 

not  try  to  do  it  sitting.  Peters  gives  the  following  directions  for  efficiency 
in  spalling,  which  are  expressed  so  well  that  I  cannot  do  better  than  quote 
his  own  words/  with  which  my  own  experience  has  been  entirely  in  accord- 
ance. 

"The  style  of  hammer  is  seldom  suited  to  the  purpose,  though  both  the 
amount  of  labor  accomplished  and  the  personal  comfort  of  the  workmen 
depend  more  upon  the  weight  and  shape  of  this  implement  and  its  handle 
than  on  any  other  single  factor,  save  the  quality  of  the  ore  itself.  There 
should  be  several  cast-steel  sledges,  differing  in  weight  from  6  to  14  lb., 
intended  for  general  use  in  breaking  up  the  larger  fragments  of  rock  to  a 
size  suitable  for  the  light  spalling-hammers.  Each  laborer  should  be  pro- 
vided with  a  hammer  6  in.  in  length,  forged  from  a  1-5  in.  octagonal  bar  of 
the  best  steel,  and  weighing  about  2-75  lb.  This  should  be  somewhat  flat- 
tened and  expanded  at  the  middle  third,  to  give  ample  room  for  a  handle  of 
sufficient  size  to  prevent  frequent  breakage.  The  handles  usually  sold  for 
this  purpose  are  a  constant  source  of  annoyance  and  expense,  being  totally 
unsuited  to  this  peculiar  duty.  It  is  better  to  have  the  handles  made  at  the 
works,  if  it  is  possible  to  procure  the  proper  variety  of  oak,  ash,  hickory,  or 
best  of  all,  a  small  tree  known  in  New  England  as  ironwood  (hornbeam), 
which,  when  peeled  and  used  in  its  green  state,  excels  most  other  woods  in 
toughness  and  elasticity.  The  handles  should  be  perfectly  straight,  without 
crook  or  twist,  so  that,  when  firmly  fastened  in  the  eye  of  the  hammer  by  ai 
iron  wedge,  the  hammer  will  hang  exactly  true.  Their  value  and  durability 
depend  much  upon  the  skill  with  which  the  handles  are  shaved  down  to 
area  less  than  half  their  maximum  size,  beginning  at  a  point  about  6  ii 
above  the  hammer-head  and  extending  for  about  10  in.  toward  the  fi 
extremity.  If  properly  made  and  of  good  material,  they  may  be  made 
small  as  to  appear  likely  to  break  at  the  first  blow,  but  in  reality  they  ar( 
so  elastic  that  they  act  as  a  spring,  and  obviate  all  disagreeable  effects  of 
shock,  wear  longer  and  do  more  work  than  the  ordinary  handle.  Such 
handle  has  lasted  five  months  of  constant  use  in  the  hands  of  a  carefi 
workman,  whereas  one  of  the  ordinary  make  has  an  average  life  of  scarce! 
four  days,  or  perhaps  30  tons  of  ore. 

"Where  the  ore  is  of  fairly  uniform  character,  it  is  advantageous  to  ado] 
the  contract  system  for  this  kind  of  work.  A  skilful  laborer,  under  ordr 
nary  conditions,  will  break  seven  tons  of  rock  per  10-hour  shift  to  a  size  of 
2-5  in.,  taking  coarse  and  fine  as  it  comes,  and  in  some  cases  is  also  able 
to  assist  in  screening  and  loading  the  ore  into  cars.  The  latter  operation 
should  bo  executed  with  a  strong  potato-fork  having  such  spaces  between 

'  Op.  clt.,  p    93. 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES. 


the  tines  as  to  retain  the  coarsest  size,  while  the  finer  classes  are  left  upon 
the  ground.  The  amount  of  space  required  for  convenient  spalling  is  about 
40  sq.  ft.  per  man,  which  will  allow  for  ore-dumps,  tracks,  sample  boxes, 
etc.  A  good  light  is  essential." 

CULLING. — The  ore  having  been  broken,  either  by  machine  or  by  hand,  it 
must  be  passed  over  a  screen  or  grizzly  to  remove  the  fines,  which  will  be 
sent  directly  to  the  dressing  floors,  before  going  to  the  sorters.  The  latter 
will  be  probably  either  men  who  are  incapacitated  for  other  work  or  boys. 
In  Europe,  women  and  girls  are  frequently  employed  for  such  work,  but 
American  ideas  would  scarcely  permit  that.  Boys  become  very  expert  in 
the  work  and  are  satisfied  by  materially  lower  wages  than  men,  compared 
with  whom  they  are  equally  or  more  alert  and  efficient.  In  sorting  ore  by 


FIG.  19. — TRANSVERSE  SECTION  OF  SPALLING  AND  SORTING  HOUSE. 

hand  the  success  of  the  operation  depends  largely  upon  the  convenience  of, 
the  manner  in  which  the  ore  is  presented  to  the  pickers.  This  may  be  done 
by  stationing  the  latter  along  a  bench  on  which  they  may  draw  from  pockets 
the  ore  to  be  sorted;  better  by  discharging  the  ore  on  a  large,  circular  or 
annular  table  of  wood  or  iron,  revolved  slowly,  around  the  periphery  of 
which  the  pickers  stand;  or  better  still,  by  discharging  it  on  a  traveling 
belt  from  which  the  pickers  can  select  it. 

Stationary  Tab  les. — An  arrangement  of  the  first  kind  at  a  mine  in  Mexico 
for  sorting  an  ore  composed  of  blende,  pyrite,  galena  and  quartz,  which  was 
to  be  separated  into  those  four  classes,  is  shown  in  the  accompanying  en- 
graving, Fig.  19.  The  spallers  on  the  upper  floor  received  the  ore  from  the 
mine  car?  through  a  chute.  They  broke  it  to  2-5  in.  size  by  means  of  long 


238 


PRODUCTION    AND   PROPERTIES    OF   ZINC. 


hammers  and  shoveled  their  product  on  grizzlies,  whence  the  coarse  slid 
into  the  pockets  designed  for  it  and  the  fines  passed  through  into  a  bin, 
whence  they  were  taken  to  the  jigs.  The  sorters,  seated  along  a  bench  jn 
front  of  the  ore  pocket,  drew  ore  from  holes  in  the  latter  and  dropped  the 
various  kinds  through  holes  in  the  bench,  beneath  which  sacks  were  sus- 
pended to  receive  them. 

A  similar  arrangement,  but  on  a  larger  scale,  is  to  be  seen  *at  the  dressing 
works  at  Clausthal  in  the  Upper  Harz,  Germany,  where  the  sorting  house 
is  somewhat  according  to  the  design  shown  in  Fig.  20.  At  those  works  the 
ore  is  crushed  to  60  mm.  size  and  passed  over  a  screen  with  32  mm.  holes  in 
a  separate  house,  The  stuff  from  32  to  60  mm.  size  is  trammed  to  the  sort- 


Cobbiug  bench 


Sorting  bench 


/  \ 


FIG.  20. — TRANSVERSE  SECTION  or  ORE  SORTING  HOUSE. 

ing  house,  where  it  is  dumped  into  the  ore  pockets,  the  tramway  passing  over 
^the  latter.  The  ore  pockets  have  a  sorting  bench  on  each  side.  The  pickers 
throw  the  various  kinds  of  ore  into  boxes  placed  conveniently  on  the  floor 
and  the  waste  into  chutes  in  the  floor.  The  mixed  ore  which  is  sorted  out 
is  cobbed  and  resorted  at  benches  along  the  sides  of  the  house. 

Revolving  Tables. — An  annular,  revolving  picking  table,  as  built  by  Fraser 
&  Chalmers,  of  Chicago,  is  shown  in  Fig.  21.  The  broken  ore  is  led  on  the 
table  by  a  chute,  and  spreading  out  is  carried  by  the  revolution  of  the  table 
until,  meeting  an  inclined,  stationary  scraper,  it  is  swept  off  into  a  chute, 
which  delivers  it  into  cars,  or  a  continuous  conveyor,  to  transport  it  to  the 
next  operation.  Around  the  table  boys  stand,  who  pick  out  mineral  from 
the  slowly  moving  layer  of  ore.  The  table  itself  is  made  of  punched  iron 
or  steel  plate. 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES. 


239 


FIGS.  21  AND  22. — ORE  PICKING  TABLE. 

Fig.  21  :    Plan.     Fig.  22  :    Vertical  Section. 


240  PRODUCTION   AND   PROPERTIES   OE   ZINC. 

Experience  has  demonstrated  that  it  is  easiest  for  pickers  to  throw  the 
sorted  material  in  front  of  them,  and  this  arrangement  is  easily  made  with 
tables  of  annular  form,  in  connection  with  which  a  conical  surface  may  be 
arranged  inside  the  ring,  around  the  vertical  axis,  with  radial  partitions 
to  separate  different  classes  of  ore  which  will  slide  down  the  cone  into 
proper  receptacles.  With  stationary  tables,  and  endless  belts  where  picking 
is  done  from  both  sides,  it  is  generally  necessary  for  the  pickers  to  throw 
the  sorted  ore  backward  instead  of  forward. 

Endless  Belt  Tables. — Endless  belt  picking  tables  require  no  detailed  de- 
scription beyond  the  statement  that  they  may  be  made  of  linked  tablets  of 
wood  or  iron,  or  billets  of  wood,  or  ordinary  rubber  belting. 
The  Eobins  system  of  belt  conveyors  is  easily  adapted  to  this 
purpose,  and  the  Eobins  Belt  Conveying  Co.  makes  a  special  picking 
belt,  which  is  very  good.  It  is  heavy  and  wide,  commonly  32  to  36 
in.,  and  is  supported  on  idlers  which  are  so  shaped  as  to  give  the  belt  a 
broad,  flat  surface  at  the  center,  with  narrow,  very  slightly  raised  sides.  It 
is  made  to  travel  at  speeds  of  30  to  60  ft.  per  minute.  Owing  to  its  elasticity 
the  belt  will  withstand  spalling  of  the  ore  directly  upon  its  surface.  A  belt 
carried  300,000  tons  of  ore  in  three  years  for  the  Stirling  Iron  and  Zinc  Co. 
at  North  Mine  Hill,  N".  J.,  without  appreciable  wear,  although  a  good  deal 
of  the  ore,  which  averaged  5  in.  in  size,  was  broken  with  hammers  directly 
on  the  belt.  Rubber  belt  tables  have  the  advantage  over  other  kinds  that 
there  are  no  links  to  wear  and  no  crevices  wherein  pieces  of  ore  can  jam. 

Efficiency  in  Hand  Sorting. — To  secure  the  maximum  efficiency  in  hand 
sorting,  it  is  necessary  to  have  good  supervision  (since  any  system  of  con- 
tract work  is  difficult  to  carry  out),  good  light,  and  all  arrangements  which 
may  increase  the  convenience  of  the  pickers.  If  a  moving  table  be  used  and 
more*  than  one  class  of  ore  is  to  be  made,  it  is  best  to  have  one  boy  assigned 
to  each  kind  of  mineral,  at  least  at  the  head  end  of  the  table.  Thus  if  the 
ore  were  to  be  sorted  into  galena,  blende  and  waste,  the  first  boy  would  pick 
galena,  the  second  blende  and  the  third  waste.  One  boy  cannot  adyan- 
tageously  pick  more  than  two  classes  from  a  moving  table.  It  goes  almost 
without  saying  that  the  layer  of  ore  must  not  be  put  on  the  table  so  that  any 
part  of  it  will  not  be  in  easy  reach  of  the  pickers.  The  work  of  the  latter 
is  facilitated  by  wetting  the  ore  before  it  comes  to  them,  when  the  com- 
ponent minerals  are  much  more  easily  distinguished  than  in  dry,  dust- 
covered  condition. 

The  cost  of  culling  mineral  is  so  entirely  dependent  upon  the  character 
of  the  ore  and  the  local  conditions  of  labor  that  it  is  useless  to  cite  examples 
from  practice ;  the  probable  economy  must  be  determined  by  experiment  in 


FIGS.  23  AND  24. — BOBINS  CONVEYING  AND  PICKING  BELT. 

Fig.  23:  Installation  at  plant  of  Tennessee  Copper  Co.   Isabella,  Tenn       Fig. 24:  At  works  of 
British  Columbia  Copper  Co.   Anacon,da,  B,  C, 


MECHANICAL   CONCENTRATION    OF   ZINC   ORES.  241 

each  particular  case.  In  Europe,  especially  in  some  of  the  older  works, 
culling  is  carried  to  a  degree  of  subdivision  which  would  not  be  done  in 
modern  practice;  certainly  not  under  American  conditions.  In  the  United 
States  a  breaking  of  the  ore  by  spalling,  preliminary  to  culling,  would  be 
recommended  probably  only  in  exceptional  instances;  especially  in  those 
where  the  blende  is  of  such  occurrence  that  the  saving  in  mineral  by  avoid- 
ing loss  in  slimes  is  more  than  enough  to  offset  the  cost  of  spalling  plus 
that  of  culling,  inasmuch  as  the  cost  of  milling  the  rejected  ore  per  ton 
would  be  the  same,  substantially  if  not  identically,  as  if  all  the  ore  from 
the  mine  went  directly  to  the  mill. 

Under  ordinary  circumstances  culling  would  be  advised  probably  as  a 
step  in  the  milling  process,  where  all  the  ore  from  the  mine,  having  been 
broken  by  a  crusher  to  the  size  determined  for  the  next  machine,  would  pass 
over  a  grizzly  or  through  a  trommel  from  which  the  coarse  material  would 
go  to  the  picking  table  and  the  rejected  stuff  from  the  latter  to  the  next 
crushing  machine.  In  this  case  there  would  be  no  extra  cost  for  crush- 
ing, and  only  the  cost  of  culling,  minus  the  cost  of  milling  the 
mineral  picked  out,  would  have  to  be  considered  against  the  in- 
creased saving  of  mineral.  For  example,  if  the  cost  of  milling 
be  25c.  per  ton  of  crude  ore  and  five  tons  be  concentrated  into 
one,  the  cost  per  ton  of  concentrates  is  $1-25;  leaving  out  of  account  the 
question  of  losses  in  treatment  (very  important)  and  cost  of  repairs  on 
picking  tables,  interest,  amortization,  etc.  (comparatively  unimportant), 
it  would  be  an  equal  thing  to  produce  a  ton  of  culled  mineral  of  the  same 
grade  at  $1-50 — i.e.,  the  cost  of  the  concentrates  in  the  first  case  plus  the 
saving  of  milling  one  ton  of  material ;  the  higher  saving  of  mineral  would 
probably  permit  the  hand  sorting  to  be  done  economically  at  considerably 
higher  cost  than  $1-50  per  ton  of  product. 

GRAVITY  CONCENTRATION. 

In  concentrating  zinc  ore,  like  any  other  ore,  by  gravity  it  must  first 
be  crushed  sufficiently  fine  to  detach  the  various  component  minerals 
from  one  another,  taking  care  to  crush  as  little  as  possible  finer  than 
is  necessary  to  effect  such  a  liberation.  The  crushed  ore  is  then  separated 
into  proper  sizes,  by  screens  for  the  coarser  and  hydraulic  classifiers  for  the 
finer  sizes,  and  each  size  is  washed  separately ;  the  coarser  on  jigs,  whereby 
the  mixture  of  mineral  particles  are  shaken  up  in  water,  with  the  result 
that  the  heavier  and  more  valuable  sink  to  the  bottom;  and  the  finer  on 
shaking  tables  or  buddies,  whereby  the  lighter  worthless  mineral  is  washed 


242  PRODUCTIOX    AND   PROPERTIES    OF    ZINC. 

off,  while  the  heavier  is  discharged  by  proper  devices  as  a  concentrated  pro- 
duct. There  is  always  an  intermediate  product,  consisting  of  interlocked 
particles  of  mineral  and  gangue,  which  the  original  crushing  failed  to  sepa- 
rate. This  should  be  crushed  more  finely  by  proper  machinery  to  effect 
the  separation,  and  then  should  be  sized  and  washed  again.  The  ideal  con- 
centrating plant  conforms  to  these  conditions  and  the  better  the  details  are 
worked  out  the  lower  will  be  the  cost  of  dressing  and  the  higher  the  saving 
of  mineral,  although  in  the  best  designed  works  there  is  inevitably  a  certain 
loss  of  mineral  owing  to  some  of  it  becoming  crushed  so  finely  that  it  is 
impossible  to  settle  it  economically,  while  there  is  always  some  escaping 
attached  to  larger  or  smaller  particles  of  gangue  which  it  does  not  pay  to 
recrush  any  further. 

CARDINAL  PRINCIPLES. — The  proper  size  to  which  to  crush  the  original 
ore,  the  proper  sizes  into  which  to  divide  it  by  screens,  the  point  at  which  it 
is  best  to  discontinue  sizing  by  screens  and  begin  sorting  by  hydraulic  classi- 
fiers and  many  other  details,  are  only  to  be  determined  by  tests  and  calcula- 
tions for  each  particular  ore.  However,  experience  has  demonstrated  some 
cardinal  principles  in  ore  dressing  practice  of  which  the  more  important 
may  be  summarized  as  follows : 

Crushing. — The  comminution  of  the  ore  should  be  effected  gradually  by  a 
series  of  machines  and  never  attempted  with  one  machine ;  the  finer  it  is  to 
be  crushed,  the  more  should  be  the  members  of  the  series,  except  that  in  the 
case  of  the  ball  crushers  it  is  possible  to  effect  the  reduction  satisfactorily 
with  only  two  machines,  namely  a  rock-breaker  and  a  ball-mill,  regardless 
of  the  degree.  With  rock-breakers  and  rolls  Mr.  Philip  Argall,  who  is  a 
high  authority  on  the  crushing  of  ores,  considers  that  it  is  inadvisable  to 
attempt  a  greater  reduction  than  one  fourth  the  diameter  of  the  pieces  by 
any  one  machine.  Thus  if  the  pieces  were  of  16  in.  size  he  would  break  to 
4  in.  cubes  in  the  first  operation  and  to  1  in.  cubes  in  the  second.  If  the 
ore  were  to  be  crushed  to  0-5  in.  size  it  would  be  best  to  make  the  reduction 
in  the  ratios  of  16 :5  in.,  5  :l-5  in.,  1-5  :0-5  in.,  and  so  on.  Rock-breakers  of 
the  Gates  and  Blake  types  are  the  best  for  preliminary  crushing  machines, 
but  according  to  Mr.  Argall  rolls  are  preferable  when  the  material  is  smaller 
than  2  in.  cubes.  For  fine  crushing,  taking  the  product  of  the  breakers, 
rolls  are  generally  the  most  efficient  type  of  machine;  they  can  be  used  in 
wet  crushing,  which  is  invariably  done  in  dressing  works,  with  very  good 
results  down  to  20-mesh,  and  with  fair  results  down  to  40-mesh,  if  there 
be  not  much  clayey  matter  in  the  ore.  For  fine  grinding,  however,  the 
ball-mill  may  be  superior  to  rolls  under  certain  circumstances.  It  produces 
a  product  of  entirely  satisfactory  character  as  to  granularity,  and  has  the 


MECHANICAL    CONCENTRATION    OF    ZINC    ORFS.  243 

advantage  of  combining  the  grinding,  elevating  and  screening  apparatus  in 
one  compact  machine,  which  is  able  to  give  a  finished  product  from  coarse 
material  in  one  operation. 

Screening. — The  screening  capacity  should  be  ample  because  the  clean- 
ness of  separation  depends  largely  upon  the  perfection  of  the  sizing.  There 
should  be  two  lines  of  trommels,  duplicates  of  each  other,  through  either  of 
which  the  stream  of  ore  may  be  passed  at  will.  By  this  arrangement  the 
necessity  of  stopping  the  whole  mill  to  repair  a  single  screen  is  avoided.  In 
designing  very  large  mills  all  the  machines  may  be  advantageously  arranged 
as  a  system  of  units.  The  modern  tendency  in  ore  dressing  is  to  reduce 
the  number  of  screen  sizes.  Screens  with  apertures  smaller  than  1  or  1-5 
mm.  are  seldom  used,  the  further  grading  of  the  ore  particles  being  effected 
by  hydraulic  sorting. 

Jigging. — The  Harz  jig  is  undoubtedly  the  most  efficient  separating  ma- 
chine for  the  coarser  sizes  of  mineral  sand,  or  down  to  particles  of  1  mm. 
or  0-04  in.  diameter.  Jigs  of  special  design  are  also  very  efficient  separating 
machines  for  the  finer  sands  or  coarser  slimes.  For  a  two  mineral  separa- 
tion, e.g.,  blende  and  quartz,  a  three-sieve  jig  is  advisable ;  for  a  three  min- 
eral separation,  e.g.,  galena,  blende  and  quartz,  a  four-sieve  jig  is  preferable. 
Jigs  with  five,  six  and  even  seven  compartments  are  employed  advantage- 
ously in  the  peculiar  practice  of  the  Joplin  district.  The  improved  shaking 
tables,  like  the  Wilfley,  Cammett,  and  Bartlett,  which  are  developments  of 
the  Rittinger  side  bump  table,  have  recently  come  into  extensive  use  and 
give  excellent  results  in  separating  the  finer  sizes  of  ore.  They  have  a  wide 
range  of  application,  and  are  perhaps  the  most  efficient  fine  concentrators 
that  have  yet  been  devised. 

Slime  Washing. — A  close  saving  of  values  in  ore  dressing  can  never  be 
effected  without  a  careful  washing  of  the  slimes  which  are  unavoidably  pro- 
duced in  the  crushing  of  the  ore.  These  should  be  sorted  by  means  of  an 
hydraulic  classifier  and  then  washed  on  shaking  tables  or  buddies.  The 
coarser  climes  are  treated  advantageously  on  shaking  tables ;  for  the  finer, 
the  revolving,  convex,  circular  huddle  (round  table)  is  still  a  standard  type 
of  apparatus.1 

1  The  principles  laid  down  in  the  para-  therefrom  not  only  a  cleaner  separation  but 
graphs  on  screening,  jigging  and  slime  also  a  higher  percentage  of  recovery  than 
washing  have  been  generally  accepted  for  a  close  sizing  followed  by  jigging  and  wash- 
long  time,  but  it  must  be  confessed  that  the  ing  on  the  conventional  tables  and  buddies, 
wide  range  of  applicability  which  the  This  has  been  done  among  other  instances 
improved  shaking  tables,  like  the  Wilfley.  in  the  treatment  of  the  mixed  sulphide  ore 
have  been  demonstrated  to  possess,  has  upset  of  Leadville,  Colo.  The  tendency  of  ore 
the  old  ideas  in  some  respects.  These  tables  dressing  practice  in  the  United  States  has 
have  been  proved  capable  of  taking  pulp  been  for  a  long  time  toward  reducing  tho 
si7od  only  within  wide  limits,  and  effecting  number  of  screen  sizes  :  it  appears  now  to  be 


244 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


General  Arrangement. — As  to  the  general  arrangement  of  an  ore  dressing 
works,  the  consensus  of  the  best  engineering  opinion  at  the  present  time 
is  for  a  flat  site,  rather  than  a  hillside,  although  in  choosing  the  former  it  is 
well  to  take  advantage  of  a  natural  slope  for  a  tailings  dump,  if  that  can 
be  done  without  incurring  disadvantages  in  operation  in  other  respects.  The 
level  mill  site  is  advocated  because  the  original  construction  is  cheaper,  no 
cuts  and  fills  and  retaining  walls  being  necessary,  a  better  and  more  roomy 
arrangement  of  the  machinery  can  be  had,  besides  better  light,  more  facility 
of  supervision  and  greater  elasticity  in  extending  the  works,  while  the  extra 
cost  of  elevating  material  over  what  is  necessary  in  a  hillside  location  is 
insignificant. 

SPECIFIC  GRAVITY  OF  ZINC  AND  ASSOCIATED  MINERALS. — In  the  follow- 
ing table  are  summarized  the  specific  gravities  of  the  most  important  zinc 
minerals  and  the  impurities  which  generally  occur  with  them,  the  specific 
gravity  of  water  being  deducted  in  each  case  to  show  their  relative  weights 
when  immersed  in  water : 


SPECIFIC  GRAVITY  OF  ZINC  AND  ASSOCIATED  MINERALS. 


Mineral. 

Spec.  Gravity. 

Relative  weight 
in  water. 

Mineral. 

Spec.  Gravity. 

Relative  weight 
in  water. 

Blende  . 

3-90to4-10 

2-90to3'10 

Calcite  

2'60to2'80 

1.60  to  1-80 

Smithsonite  .. 
Franklinite.  .  . 
Zinkite..  ..... 

4'30to4-45 
5-07to5'22 
5'43to5'70 
3'58to3'80 

3'30to3'45 
4'07to4'22 
4'43to4-70 
2  '  58  to  2  '  80 

Dolomite  .... 
Barite  
Siderite  
Pyrite. 

2  -85  to  2  -95 
4'  30  to  4'  70 
3'70to3'90 
4  '  80  to  5  •  20 

1  .  85  to  1  '  95 
3.  30  to  3-70 
2'70to2'90 
3  •  80  to  4  •  20 

Willemite....  .' 
Hemimorphite 
Quartz.  . 

3'89to4'18 
3-40  to  3-50 
2  '  50  to  2  '  80 

2-89  to  3"  18 
2'40to2'50 
1  '  50  to  1  '  80 

Marcasite  
Limonite  .... 
Galena  

4'65to4-90 
3'40to3'9i 
7'20to7'60 

3'65to3-90 
2'40to2'95 
6'20to6'60 

4  •  10  to  4  '  30 

3  '10  to  3  '30 

Garnet 

3  '50  to  4  "30 

2  '50  to  3'  30 

Fluorite  '.'. 

3  -10  to  3  -20 

2-10to2'20 

Rhodonite  .  .  . 

3-50  to  3-70 

2'50to2-70 

ORE  DRESSING  IN  UPPER  SILESIA. — The  concentration  of  the  low  grade 
zinc  ores  of  Upper  Silesia  is  rendered  difficult  in  the  case  of  calamine  by  the 
earthy  and  drusy  (porous)  character  of  the  zinc  minerals  and  the  slight 
difference  between  their  specific  gravities  and  those  of  the  other  minerals 
associated  with  them ;  in  the  case  of  the  sulphide  ore  by  the  common  occur- 
rence of  marcasite  interwoven  with  the  blende.  Consequently  the  larger 
proportion  of  the  calamine  ore  produced  is  concentrated  by  hand  sorting 


toward  restricting  the  use  of  jigs  to  larger 
sizes  and  substituting  shaking  tables  for  the 
work  formerly  done  by  the  fine  jigs  and  the 
buddies.  This  tendency  is  manifested  in  its 
extreme  in  the  new  mill  of  the  Federal  Lead 
Co.  at  Flat  River,  Mo.,  which  is  to  have 
neither  jigs  nor  buddies,  but  only  shaking 
tables.  The  conventional  ore  dressing  prac- 


tice of  the  Joplin  district,  which  is  de- 
scribed further  on  in  this  chapter,  also  af 
fords  a  striking  example  of  how  an  ore  (in 
that  case  a  comparatively  easy  ore,  to  be 
sure)  can  be  jigged  successfully  without  a 
preliminary  close  classification  by  screen- 
ing. It  is  of  course  desirable  to  dispense 
with  screening  as  much  as  possible. 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES. 


and  a  good  deal  of  the  blende  is  handled  in  the  same  manner.  There  are 
certain  mines,  however,  which  mill  all  the  ore  raised.  That  is  done  at  the 
Neue  Helene  mine,  at  Scharley,  which  is  the  largest  producer  in  the  region, 
and  is  equipped  with  what  is  probably  the  best  dressing  works. 

The  Neue  Helene  dressing  works  consists  of  two  divisions,  one  for  blende 
and  one  for  calamine,  the  ore  being  divided  in  the  mine  into  those  classes. 
Both  mills  are  situated  close  to  the  main  hoisting  shaft  of  the  mine,  so  that 
the  mine  cars  are  raised  directly  to  the  highest  level  of  the  mills,  to  which 
they  are  trammed  over  a  short  bridge.  The  transverse  section  of  the  blende 


Fine  ore 


Coarse  ore 


Selected  blende 


I  Picking  table  k Trommel 

t  I  Ovor-  I ^_ 

^Undersize 


j         SpiUkasten          [ 


LD    CD    CD  CD    All    CD 


jies  Jigs  Jigs  Rittinger  tables 

FIG.  25. — DIAGRAM  OF  ORE  DRESSING  PROCESS  AT  THE  NEUE  HELENE 
BLENDE  MILL,  UPPER  SILESIA. 

mill  shows  three  steps,  with  the  first  crusher  on  the  highest  and  the  slime 
washers  on  the  lowest;  on  the  middle  step  the  mill  has  three  floors,  the 
sand  jigs  being  placed  on  the  lowest,  the  fine  crushing  rolls  and  Heberle 
mills  on  the  second  floor,  and  the  picking  tables  on  the  third  floor,  with  the 
coarse  crushing  rolls  and  the  first  train  of  trommels  on  framework  higher 
up,  but  below  the  level  of  the  first  crusher  on  the  highest  step.  The  mill 
is  therefore  arranged  on  five  levels.  The  general  scheme  of  the  ore  dressing 
system  is  shown  in  the  accompanying  diagram,  Fig.  25. 

The  crushing  rolls  are  all  geared  and  of  slow  speed,  the  first  set  of  the 


246  PRODUCTION    AND   PROPERTIES    OF   ZINC. 

series  being  900  mm.  in  diameter.  The  jigs  are  built  entirely  of  iron  and 
steel  and  have  semi-cylindrical  bottoms.  The  Rittinger  tables  are  double, 
and  also  are  built  of  iron  and  steel.  The  calamine  mill  is  of  similar  design, 
but  it  has  no  Heberle  mills,  and  small  "Stossherds"  are  substituted  for  the 
Rittinger  tables  of  the  blende  mill.  The  work  in  both  mills  is  done  largely 
by  women,  of  whom  there  is  an  army,  who  in  1893  were  paid  from  0-9 
marks  (214c.)  for  attending  the  jigs,  to  1-2  marks  (28-6c.)  for  tramming, 
12-hour  shifts.  A  small  quantity  of  galena  concentrate  is  produced,  be- 
sides the  blende.  The  works  are  driven  by  a  180  h.  p.  engine.  They  were 
built  in  1880  and  were  the  first  large  dressing  works  erected  in  Upper  Silesia. 
Some  data  as  to  the  work  done  in  them  are  given  on  p.  217. 

ORE  DRESSING  IN  MISSOURI  AND  KANSAS. — Until  recently,  that  is  to  say 
until  about  1895,  the  zinc  ore  of  the  Joplin  district  was  dressed  chiefly  by 
hand- jigging.  Since  1895  a  crude  type  of  steam  mill  has  come  into  general 
use,  and  their  cost  being  low  and  their  efficiency  high,1  they  have  almost 
completely  displaced  the  old  hand-jig  plants.  Compared  with  the  European 
practice  in  dressing  zinc  ore,  as  exemplified  in  Upper  Silesia,  the  practice  in 
the  Joplin  district  is  extremely  crude,  but  the  results  do  not  apparently 
compare  unfavorably.  This  is  because  the  Silesian  ore  is  an  intimate  mix- 
ture of  a  compact,  cryptocrystalline  blende  and  marcasite  in  a  gangue  of 
dolomite  and  frequently  clay — a  difficult  ore  to  dress ;  while  the  Joplin  ore 
is  coarsely  crystalline  blende,  with  comparatively  little  pyrites  (and  in 
many  cases  none  at  all )  in  a  gangue  of  quartz,  from  which  it  is  liberated  by 
a  comparatively  coarse  crushing — an  ideal  ore  for  gravity  dressing. 

Method  of  Milling. — The  dressing  works  in  the  Joplin  district  conform 
closely  to  a  standard  type.  Generally  they  are  designed  for  a  capacity  of 
100  tons  per  10  hours.  A  mill  of  that  size  is  provided  with  a  16X24  in. 
Blake  crusher,  delivering  into  a  storage  bin,  whence  the  crushed  ore  is  fed 
mechanically  to  a  set  of  12X36  in.  rolls,  driven  by  belts  at  35  r.  p.  m.  The 
product  of  the  rolls  is  elevated  and  discharged  into  a  36X84  in.  trommel, 
covered  with  sheet  steel  punched  with  0-5  in.  round  holes,  which  makes  20 
r.  p.  m.  The  oversize  from  this  trommel  passes  to  another  set  of  12X36  in. 
rolls,  and  having  been  crushed  finer  by  them,  it  is  delivered  back  to  elevator 
No.  1  and  trommel  No.  1.  The  product  which  passes  through  the  0-5  in. 
holes  of  trommel  No.  1  goes  to  trommel  No.  2,  which  is  also  36X84  in.,  but 
is  covered  with  plate  punched  with  0-125  in.  holes.  The  oversize  from  trom- 
mel No.  2  goes  to  the  roughing  jig;  the  undersize  to  the  sand  jig.  There 
is  also  a  cleaning  jig  which  reworks  certain  products  of  the  roughing  jig. 

The  jigs  are  of  the  Cooley  pattern,  in  which  the  box  is  built  up  with  2X4 

1  This  word  is  used  with  qualifications  which  will  be  explained  further  on. 


MECHANICAL   CONCENTRATION    OF   ZINC   ORES.  24* 

in.  scantling  laid  together  on  the  wider  sides  and  spiked  and  bolted  through, 
the  sides  of  the  box  being  thus  made  4  in.  thick.  This  has  been  proved  to 
make  a  very  solid  and  watertight  jig  box,  which  is  excellent  in  all  respects. 
The  roughing  jig  has  five  compartments,  each  30X42  in.,  with  trays  of  4- 
mesh  steel  wire  cloth ;  the  counter  shaft  is  driven  at  140  to  175  r.  p.  m.  The 
cleaning  jig  has  six  compartments,  30X36  in.  (sometimes  26X42  in.),  with 
trays  of  4-  and  6-mesh  brass  wire  cloth;  the  counter  shaft  is  driven  at 
170  to  225  r.  p.  m.  The  sand  jig  has  four  or  six  compartments  with  24X36 
in.  or  25X30  in.  trays  of  12-  and  14-mesh  brass  wire  cloth;  the  counter  shaft 
is  driven  200  to  260  r.  p.  m. 


Crude  ore 


Tailings 

Concentrates 

FIG.  26. — DIAGRAM  OF  THE  ORE  DRESSING  PROCESS  EMPLOYED  IN  THE 
JOPLIN  DISTRICT,  Mo. 

The  roughing  jig,  which  receives  material  finer  than  0-5  in.  and  coarser 
than  0-125  in.,  furnishes  a  clean  concentrate  from  above  the  sieves  of  the 
first  two  compartments.  The  third,  fourth  and  fifth  compartments  yield  a 
mixed  product,  which  is  conveyed  to  a  third  set  of  12X36  in.  rolls,  set  to 
crush  fine.  The  product  of  these  rolls  is  united  with  those  of  rolls  Nos.  1 
and  2,  and  is  passed  again  through  the  screens.  The  concentrate  made 
through  the  sieve  of  each  compartment,  which  ranges  in  size  from  0445  to 
0-125  in.,  is  delivered  by  means  of  a  belt  elevator  to  the  cleaning  jig.  The 
latter  makes  a  clean  concentrate  both  above  and  below  the  sieves  in  three 
or  four  compartments.  The  mixed  product  from  above  the  sieves  of  the 


248  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

other  compartments  is  recrushed  by  rolls  No.  3  and  is  returned  to  the  system 
through  the  trommels;  the  hutch-work  is  delivered  to  the  sand  jig.  The 
sand  jig  also  receives  the  undersize  from  screen  No.  2.  It  makes  clean 
heads  and  clean  tails.  The  above  scheme  is  illustrated  in  the  accompanying 
diagram,  Fig.  26. 

The  variations  from  the  system  described  above  are  slight  and  exceptional. 
In  some  mills  the  rolls  are  smaller  than  12X36  in.  (14X24  in.  being  a  com- 
mon size),  and  in  some  the  third  set  is  omitted.  Some  mills  have  only  one 
sizing  trommel  and  some  have  three,  one  with  0-375  in.  holes  being  inter- 
polated between  0-5  and  0-125  in.  In  exceptional  cases  the  finest  product 
is  sorted  by  means  of  a  pointed  box,  of  which  the  overflow  is  washed  on  a 
Frue  vanner.  Sometimes  the  slimes  are  settled  in  tanks  and  reworked  by 
the  so-called  Emmons  sludge  system.  Wilfley  tables  have  recently  been  in- 
troduced for  washing  the  finer  products ;  they  are  said  to  have  given  satis- 
factory results.  In  general,  all  the  tailings  of  the  mill  are  conveyed  to  the 
boot  of  a  16-in.  belt  elevator,  50  ft.  high  from  center  to  center,  by  which 
they  are  discharged  on  the  dump.  This  arrangement  is  necessary  inasmuch 
as  all  the  mills  of  the  district  are  built  on  level  ground. 

The  jig  room  is  approximately  24X64  ft.;  the  engine  and  boiler  room 
30X28  ft.  The  machinery  is  driven  usually  by  a  60  h.  p.  slide  valve  engine, 
for  which  the  steam  is  furnished  by  a  100  h.  p.  horizontal  tubular  boiler. 
The  cost  of  these  mills  is  $6,000@$8,000  for  a  nominal  capacity  of  10  tons 
per  hour.  With  brittle,  flint  ore,  which  is  crushed  easily,  that  capacity  is 
often  attained,  but  with  clayey  ore  which  tends  to  choke  up  the  crushing 
machinery  the  capacity  may  be  reduced  to  as  little  as  five  tons  per  hour. 
The  crushing  machinery  that  is  used  is  of  an  inferior  class  and  is  subject  to 
frequent  break-downs,  thus  reducing  the  average  capacity  of  the  mill.  The 
regular  mill  crew  comprises  four  men,  viz.,  two  crusher-feeders,  one  jig 
man  and  an  engine  tender. 

Cost  of  Treatment. — The  objects  chiefly  aimed  at  in  the  existing  ore  dress- 
ing practice  in  the  Joplin  district  are  (1)  to  put  through  the  maximum 
quantity  of  ore  per  day  that  a  unit  crew  of  men  can  handle,  reducing  the 
cost  of  dressing  per  ton  of  crude  ore  to  the  minimum,  and  (2)  the  pro- 
duction of  a  concentrate  which  will  meet  the  market  requirements  and  fetch 
the  best  price.  In  the  attainment  of  those  objects,  ore  is  crushed  and  jigged 
in  the  largest  and  best  works  for  as  low  as  20c.  per  ton  (mill  men  being 
paid  $2-00@$2-25  per  day  and  coal  costing  $1-40@$1-60  per  ton  for  mine 
run),  while  a  concentrated  product  assaying  from  57  to  65%  Zn,  the  late 
being  practically  pure  blende,  is  obtained. 

The  cost  of  ore  dressing  in  the  Joplin  district  varies  between  wide  limrl 


MECHANICAL    CONCENTRATION    OF    ZINC    OKI  b.  -4(J 

not  only  among  various  mills,  but  also  in  the  same  mill.  The  variation 
between  different  mills  of  the  same  design  and  efficiency  is  due  to  differ- 
ences in  the  character  of  the  ore  milled.  The  variations  in  the  same  mill 
are  ascribable  largely  to  the  inferior  class  of  crushing  machinery  which  is 
employed.  Break-downs  are  frequent,  leading  to  large  bills  for  repairs  and 
renewals,  but  more  important  than  that  to  great  losses  of  time.  This  is 
shown  in  the  records  of  single  mills,  wherein  the  cost  may  be  as  low  as 
20c.  per  ton  of  crude  ore  in  one  month  and  40c.  per  ton  in  the  next  month, 
For  this  reason  it  is  quite  unsafe  to  base  comparisons  on  the  results  of  a 
single  month. 

The  cost  of  dressing  for  six  consecutive  months  in  three  different  mills, 
for  which  a  careful  record  was  kept,  was  as  follows : 


MILL  No.  1 

MILL  No.  2 

MILL  No.  3 

Tons 

Cost 

Tons 

Cost 

Tons 

Cost 

Tons 

concen- 

per ton 

Tons 

concen- 

per ton 

Tons 

concen- 

per ton 

ore 

trate 

Of 

of  ore 

ore 

trate 

%) 

of  ore 

ore 

trate 

ftj. 

of  ore 

milled 

pro- 
duced 

milled 

milled 

pro- 
duced 

milled 

milled 

pro- 
duced 

milled 

3,461 

•     231 

6-7 

$0-550 

3,685 

130 

3-5 

$0-28 

3,431 

213 

6-2 

$0-44 

3,985 

313 

7'9 

0-245 

3,413 

202 

5-9 

0-26 

4,251 

165 

3-9 

0  44 

4,914 

259 

5'3 

0-190 

3,812 

186 

4-9 

0-29 

8,410 

430 

5-1 

0-37 

5,710 

259 

4-5 

0-200 

4,196 

211 

5-0 

0-24 

9,904 

268 

2-7 

0*29 

5,130 

229 

4'5 

0-180 

2,695 

147 

5'5 

0-25 

3,607 

167 

4-6 

0-44 

2,295 

135 

6-0 

0-32 

5,283 

284 

5-4 

0-38 

o4,640 

258 

5-6 

0-270 

3,349 

169 

5-0 

0-27 

5,814 

254 

4-4 

0-39 

a  This  line  gives  the  averages  for  the  six  months,  except  in  the  case  of  Mill  No.  1,  which 
was  idle  during  the  last  month  of  the  period. 


Loss  of  Mineral. — The  production  of  a  concentrate  assaying  63%  Zn  and 
even  one  of  60%  Zn,  which  is  thought  to  be  approximately  the  average  of  the 
entire  district,  is  certainly  successful  work,  but  it  is  accomplished  at  the 
cost  of  the  mineral  in  the  ore.  The  mills  of  the  district  are  characterized 
by  the  absence  of  means  for  treating  slimes1  and  large  losses  are  experienced 
naturally  on  that  account,  though  since  the  ore  does  not  require  very  fine 
crushing  the  losses  of  slime  are  less  than  would  be  the  case  otherwise,  while 
it  is  an  established  fact  in  ore  dressing  that  the  higher  the  degree  of  con- 
centration the  higher  are  the  losses  of  mineral. 

As  to  what  the  losses  in  dressing  experienced  in  the  Joplin  district  actually 
are,  it  is  difficult  to  conclude,  there  being  few  mills  at  which  the  concentrates 
are  assayed  for  zinc,  or  even  for  their  moisture  content  when  weighed,  and 

1  This  has  lately  been  rectified  in  some  of  the  better  mills,  wherein  vanners  and  shak- 
ing tables  have  been  introduced. 


250  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

fewer  still,  perhaps  it  is  safe  to  say  none  at  all,  where  the  crude  ore  put 
through  them  is  weighed  and  assayed.  In  the  absence  of  these  data  it  is 
impossible  to  determine  accurately  the  percentage  of  mineral  that  is  lost. 
Carl  Henrich,  in  1892,  discussed  the  subject  in  the  following  words  i1 

"When  we  look  at  the  tailing  piles,  and  see  the  vast  amount  of  good  blende 
left  in  them;  when  we  follow  the  course  of  the  water  flowing  from  these 
concentration  works  into  larger  streams,  and  see  everywhere  the  fine  blende 
shining  golden  yellow  in  a  bright  sunlight,  we  begin  to  doubt  the  success  of 
a  method  of  concentration,  which  on  an  average  wastes  certainly  not  less 
than  one-third,  and  more  frequently  nearly  one-half,  of  the  ore  contained 
originally  in  the  crude  material  treated.  No  doubt  this  assertion  of  losses 
will  be  denounced  as  an  exaggeration  by  most  practical  miners  in  Webb 
City.  But  I  believe  a  fairly  conducted  test  will  demonstrate  that  no  con- 
centrating works  near  Webb  City,  as  at  present  conducted,  recovers  more 
that  two-thirds  (probably  much  less)  of  the  blende  contained  in  the  orig- 
inal mine-stuff  hoisted  to  the  surface."  Henrich's  conclusions  in  1892  have 
been  borne  out  by  the  considerable  quantity  of  mineral  which  has  been  re- 
covered from  accumulations  of  old  tailings  by  the  operators  of  "sludge 
mills." 

The  percentage  of  mineral  recovered  from  the  ore  milled  in  the  Joplin 
district  varies  considerably  according  to  the  character  of  the  ore,  which 
differs  more  or  less  in  various  parts  of  the  district.  Some  tests  made  re- 
cently have  indicated  that  80%  of  the  mineral  in  certain  docile  ores  is 
recovered,  while  in  the  case  of  certain  refractory  ores  the  recovery  may  not 
be  more  than  50%.  It  is  conservative  to  conclude  that  a  recovery  of  70% 
represents  good  average  work  in  ore  dressing  in  the  Joplin  district  at  the 
present  time.  There  is  little  probability  that  the  figure  is  any  higher,  and 
it  may  be  no  more  than  66%%.  It  is  proper  to  remark  in  this  connection 
that  a  mineral  recovery  of  80%  is  high  in  dressing  any  kind  of  ore  in  a 
perfectly  designed  mill,  and  if  it  be  possible  to  save  as  much  as  70%  by 
the  Joplin  practice  it  is  indicative  chiefly  of  the  docility  of  the  ore.2 

1  "Zinc    Blende    Mines    and    Mining    near  signed   upon   the  most  approved   principles 
Webb    City,    Mo.,"    Trans.    Am.    Inst.    Min.  and   is   well    equipped   with   machinery   for 
Eng.,  XXI,  23.  carefully    sizing    the    ore,    recrushing    mid- 

2  A  saving  of  96%  is  extraordinarily  high.  dlings  and  washing  the  slimes.     The  coarse 
but  is  sometimes  attained  under  favorable  sand    is    washed    on    jigs,    the    medium    on 
conditions.     According   to   a    paper    in    the  Bartlett  tables   (a  modification  of  the  Wil- 
Eng.  &  Min.  Journ.  of  July  20,  1901,  care-  fley),  and  the  fine  on  vanners.     The  ore  is 
ful  tests  at  the  new  mill  of  the  Moctezuma  chalcopyrite    (sp.    gr.   4-2)    in   a   gangue   of 
Copper    Co.    at    Nacosari,    Sonora,    Mexico,  rhyolite   (sp.  gr.  2-5).     The  high  saving  of 
showed  a  recovery  of  86%  of  the  mineral  in  mineral  is  "due  largely  to  the  fact  that  the 
the  first   16,000   tons   of  ore   milled,   while  sulphide   is  solid  and   coarse   and   does   not 
subsequent  improvements  raised  the  recov-  permeate     the     solid     fragments     of     the 
ery   to  90%.       The  mill   is   apparently   de-  gangue."     Another  example  of  an  apparent- 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES.  251 

It  is  not  to  be  thought  that  the  Joplin  miners  and  mill  men  are  not 
aware  that  they  are  losing  a  great  deal  of  ore  value  that  might  be  saved.  On 
the  contrary,  they  are  quite  alive  to  that  fact,  but  the  continuance  of  the 
milling  practice,  which  Henrich  and  many  others  after  him  have  criticized 
so  severely,  is  due  to  the  conclusion  that  it  is  the  most  profitable.  This 
conclusion  may  be  incorrect,  but  it  should  not  be  lightly  rejected,  as  many 
innovators  with  preconceived  opinions  as  to  the  crudity  of  the  Joplin 
method  have  learned  in  a  costly  manner.  The  present  practice  is  the  con- 
crete result  of  the  experience  of  many  men  extending  over  many  years,  which 
has  naturally  evolved  a  system  that  conforms  to  the  peculiar  conditions  of 
the  district.  Further  improvements  will  be  made,  without  doubt,  but  they 
are  much  more  likely  to  originate  in  the  district  than  outside  of  it. 

A  modification  of  the  method  which  will  afford  an  increased  saving  of  the 
mineral  of  the  ore  milled  is  one  of  the  improvements  that  are  likely  to  be 
made  in  the  future.  If  a  mill  be  operated  on  ore  which  yields  a  concen- 
trate of  5%,  without  saving  anything  from  slimes,  and  the  coarse  tailings 
assay  2  to  2-5%  mineral;1  if  the  slimes  can  be  impounded  and  reworked 
profitably  by  tributers,  and  if  after  an  accumulation  of  tailings  has  been 
made  they  can  be  profitably  remilled  by  men  who  make  a  specialty  of  that 
business;2  if  those  things  can  be  done  (they  are  done,  in  fact),  it  would 
appear  best  to  do  them  in  connection  with  the  original  handling  of  the 
material  and  deposit  the  waste  products  in  a  final  resting  place.  Rational 
as  this  proposal  appears  to  be,  the  reasons  why  it  has  not  been  done,  and 
why  perhaps  it  will  never  be  done,  are  not  difficult  to  perceive.  The  Joplin 
mill  men  as  a  class  are  not  familiar  with  slime  dressing.  The  ore  bodies 
of  the  district  are  of  variable  magnitude  and  frequently  are  exhausted 
quickly.  The  method  of  mining  does  not  open  reserves  of  ore,  and  the  life 
of  a  mine  is  uncertain.  The  margin  over  the  cost  of  mining  and  milling 
is  likely  anyway  to  be  narrow.  The  capital  of  the  men  exploiting  the  mines 
is  generally  small.  All  of  these  conditions  tend  to  limit  the  expenditure 
for  original  plant  to  the  least  that  will  enable  the  mine  to  be  worked.  In 
order  to  meet  that  requirement  a  type  of  mill  has  been  evolved  which  costs 
only  $30@$40  per  ton  of  daily  capacity  (as  compared  with  $150@$200  for 

ly  easy  two  mineral  separation  is  afforded  brittleness  of  galena  causes  it  to  go  largely 

by  the  lead  ore  of  the  Flat  River  and  Bonne  into  the  slime, 

Terre    districts    in    St.    Francois    Co.,    Mo.,  x  The    tailings    made    in    the    district    are 

where    galena     (sp.    gr.    7-4)     occurs    in    a  sometimes  as  low  as  1%  Zn,  but  sometimes 

gangne  of  dolomite  (sp.  gr.  2-9).    The  mills  are  as  high  as  3%;  much  depends  upon  the 

are  of  large  capacity  and  well  equipped,  but  character  of  the  ore. 

only  about  72%  of  the  mineral  in  the  ore  is  2  Under      favorable      conditions      tailings 

recovered.     The  fact  that  the  recovery  is  no  yielding  as  little  as  1-5%  mineral  have  been 

higher  is  due  to  the  fine  dissemination   of  reworked  profitably. 

the   galena   through   the  gangue,   while  the 


252 


PBODUCTION    AND  PROPERTIES    Ol1   ZINC. 


an  ordinary  mill  in  other  districts).1  The  design  has  become  well  estab- 
lished, one  mill  resembling  90%  of  all  the  others  in  the  district  like  peas  in 
a  pod,  and  the  developer  of  a  new  mine  can  contract  for  the  erection  of  a 
mill  as  easily  as  he  can  for  a  barn  and  with  as  little  concern  as  to  its  promised 
efficiency  in  operation.  The  addition  of  recrushing  and  slime  washing  ma- 
chinery would  introduce  unfamiliar  complications  and  would  increase  the 
first  cost.  The  complications  might  be  learned,  of  course,  but  the  increased 
cost  would  always  raise  doubts  as  to  the  advisability  of  the  additional  invest- 
ment until  the  mine  had  been  tested.  Hence  it  is  that  the  reworking  of 
tailings  has  been  left  until  a  sufficient  quantity  has  accumulated  to  make  it 
worth  while. 

Total  Cost  of  Production. — The  cost  of  dressing  in  the  general  run  of 
the  plants  in  the  Joplin  district  probably  averages  about  30c.  per  ton  of 
crude  ore.2  The  cost  of  mining  is,  of  course,  variable.  The  general  average 
for  six  months  of  five  mines  which  produced  about  120,000  tons  of  crude 
ore,  yielding  about  6,000  tons  of  concentrates,  was  70c.  per  ton  of  crude  ore, 
the  extremes  being  56c.  and  94c.  General  expense  and  amortization  of  plant 
were  not  included,  however.  Frank  Nicholson  states3  that  mining  has  been 
done  as  low  as  30c.  per  ton  in  certain  of  the  properties  under  his  manage- 
ment, while  in  others  the  cost  has  been  $1-00.  The  mean  between  those 
extremes  is  65c.  All  of  the  figures  quoted  above  refer  to  the  operations  of 
large  companies,  which  are  subject  to  a  general  expense  of  perhapfc  lOc.  per 
ton  of  crude  ore  over  and  above  the  cost  of  mining  and  milling. 

The  minimum  and  average  cost  of  mining  and  milling  100  tons  of  ore  in 
the  Joplin  district  are  approximately  as  follows : 


Item 

Minimum. 

Average. 

Mining  
Milling 

$30-00 
25-00 

$70-00 
30-00 

General  expen-e  

lO'OO 

10-00 

Total  

$65-00 

$110-00 

1  These  figures  refer  to  the  daily  capacity 
on   the  basis  of  double  shifts ;   the   Joplin 
100-ton  mill  is  run  only  one  shift. 

2  I  am  aware  that  a  lower  figure  is  some- 
times stated.     For  example,   Eric   Hedburg 
said   (in  a  paper  read  before  the  American 
Institute    of    Mining    Engineers,    Richmond 
meeting,  February,  1901)   that  the  cost  of 
milling  100  tons  per  day  would  be  $22-75= 
22-75    c.    per   ton.      That   figure,    and   even 
lower  ones,  may  be  attained  as  the  average 
of   a    single    month,    but   a    yearly    average 


would  not  be  so  low.  Hedburg  estimated 
the  cost  of  hand-jigging  at  56c.  per  ton, 
reckoning  two  men  at  grizzlies  ($3)  ; 
four  men  jigging  ($8)  ;  two  men  jigging 
($5)  ;  and  one  man  handling  waste  rock 
($1.50)  ;  total,  $17.50  for  the  concentration 
of  30  tons  of  crude  ore  per  day  of  nine 
hours.  The  substitution  of  steam-mills  for 
hand  jigs  was  one  of  the  important  econo- 
mies introduced  in  the  Joplin  district  be- 
tween 1891  and  1900. 

'The  Mineral  Industry,  VIII,  677. 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES. 


253 


The  cost  of  production  per  ton  of  mineral  from  ore  yielding  3  to  8% 
of  concentrate  is  consequently  more  or  less  as  follows : 


Yield 

Ratio 

Minimum 

Average 

Yield 

Ratio 

Minimum 

Average 

3% 

4% 

5% 

33^:1 
25:1 
20-1 

$21-66 
16-25 

i:roo 

$36  66 
27'SO 
22-00 

6% 

7% 
8% 

161:1 
14^:1 
12^:1 

$10*83 
9'29 
8-12 

$18-33 
15-73 
13-75 

The  ultimate  cost  of  production  is  greater  than  is  indicated  by  the  above 
figures,  because  of  the  charges  which  must  be  made  for  interest  on  the  capital 
invested  and  amortization  of  the  cost  of  plant  and  land,  exploration  and 
development  work,  etc.1  Under  the  leasing  system  the  charges  on  the  land 
and  some  of  the  dead  work  are  covered  by  the  royalty  of  15  to  25 %,  which 
is  deducted  from  the  proceeds  of  the  ore  as  the  share  of  the  land  owner  and 
prime  lessee — i.e.,  if  mineral  sells  for  $25  per  ton  the  miner  realizes  $2 1-2 5  @ 
$18*75.  Besides  his  product  of  zinc  ore,  however,  he  recovers  as  a  by- 
product, so  to  speak,  a  certain  quantity  of  lead  ore,  worth  $40@$48  per 
ton,  but  subject  to  a  royalty  ranging  up  to  33%%.  The  proportion  of  lead 
ore  to  zinc  ore  varies  in  different  mines,  but  the  average  for  the  whole  dis- 
trict is  approximately  1 :10 ;  the  statistics  as  to  this  have  been  given  on 
page  188. 

It  is  impossible,  to  arrive  at  any  reliable  conclusion  as  to  the  average 
grade  of  the  ore  now  mined  in  the  Joplin  district,  but  it  is  probably  in  the 
neighborhood  of  4-3%  Zn=6-4%  blende,  corresponding  to  a  yield  of  5% 
of  mineral  assaying  60%  Zn  on  the  assumption  that  70%  of  the  content  of 
the  ore  be  recovered.  This  is  indicated  by  the  fact  that  the  production  of 
the  district,  which  was  considerably  stimulated  by  the  high  prices  for  ore  in 
1899,  was  not  materially  restricted  by  the  decline  in  price  in  1900,  and 
actually  increased  in  1901,  when  60%  ore  sold  at  $24@$25.  In  the  early 
part  of  the  decade  1891-1900  the  average  grade  of  the  ore  mined  must  have 
been  higher,  inasmuch  as  there  was  a  steadily  increasing  production  on  a 
market  which  was  generally  below  $24. 

RELATION  BETWEEN  ORE  DRESSING  AND  SMELTING. —  In  dealing  with  a 
zinc  ore  which  requires  a  preliminary  mechanical  concentration  before  smelt- 
ing, it  is  important  to  adjust  the  method  of  dressing  with  respect  to  the 
conditions  of  smelting  in  such  a  way  that  the  margin  between  the  value  of 
the  ultimate  products  and  the  total  cost  of  production  will  be  the  maximum 
possible.  This  is  especially  important  where  the  same  company  operates 

1  The  cost  of  opening  a  mine  in  the  Joplin  district  and  equipping  it  with  the  necessary 
machinery,   concentrating  mill,  etc.,   is  generally  about  $10,000@$15,000. 


254  PRODUCTION    AND    rKOPEKTlKS    OF    ZINC. 

both  mines  and  smelting  works,  and  is  therefore  relieved  of  the  necessity 
of  conforming  to  the  more  or  less  arbitrary  requirements  of  independent 
smelters.  In  any  case,  the  smelting  practice  is  the  less  capable  of  modifica- 
tion, wherefore  the  practice  in  dressing  should  be  made  to  conform  thereto. 
As  to  how  that  may  be  done  will  depend  of  course  upon  the  ore.  With 
many  ores  of  a  difficult  character  there  is  not  much  leeway  for  modification 
in  the  dressing  practice ;  with  some  ores  of  an  easy  character,  like  those  of 
the  Joplin  district,  for  example,  there  is  a  wide  latitude.  The  question  to 
be  settled,  then,  is  as  to  whether  the  lower  cost  of  smelting  a  high  grade 
ore  is  offset  by  the  increased  loss  of  metal  in  making  a  high  grade  ore,  or 
vice-versa. 

In  the  Joplin  district  at  the  present  time  the  ore  is  dressed  to  a  product 
of  60%  Zn — i.e.,  the  concentrate  must  consist  of  at  least  90%  of  mineral, 
blende.  The  loss  of  mineral  in  tailings  and  slimes  is  naturally  higher  in 
making  a  concentrate  of  that  grade  than  in  making  one  containing  only 
45%  Zn  or  67-5%  of  blende.  For  the  purpose  of  illustration,  let  it  be 
assumed  that  in  making  a  60%  concentrate  out  of  Joplin  ore  assaying  5% 
Zn,  there  will  be  a  loss  of  30%  of  zinc  in  dressing,  while  in  making  a  45% 
concentrate  out  of  the  same  ore  there  will  be  a  loss  of  only  20%.  On  this 
assumption,  100  tons  of  ore  raised  from  the  mine  would  contain  five  tons 
of  zinc,  equivalent  approximately  to  7-5  tons  of  blende.  If  30%  be  lost  in 
•dressing,  there  remains  3-5  tons  of  zinc,  equivalent  to  5-25  tons  of  blende, 
to  go  into  the  concentrate;  if  the  concentrate  assays  60%  Zn,  or  90% 
blende,  there  must  be  5-86  tons  of  concentrate.  If,  on  the  other  hand,  only 
20%  be  lost  in  dressing,  there  will  be  four  tons  of  zinc,  equivalent  to  six 
tons  of  blende,  recovered,  and  if  the  concentrate  assay  45%  Zn,  or  67-5% 
blende,  its  weight  must  be  8-89  tons.  The  only  extra  cost  in  the  mill  is 
that  of  moving  3-03  tons  of  mineral  to  the  storage  bins  and  loading  the 
increased  quantity  on  board  cars.  This  would  not  amount  to  much,  but 
in  the  transportation  and  smelting  of  the  ore  the  costs  would  count  up 
rapidly  on  the  greater  quantity  of  valueless  material  contained  in  the  ore. 

Assuming  a  freight  rate  of  $1,  a  smelting  cost  of  $9-50  and  a  metal  recov- 
ery of  86%  in  each  case,  the  results  would  be  as  computed  in  the  subjoined 
table,  if  spelter  were  worth  4c.  per  Ib. ;  from  which  it  appears  that  an  addi- 
tional saving  of  10%  mineral  at  the  expense  of  making  a  concentrate  only 
three  fourths  as  rich  would  lead  to  a  gain  of  only  about  2c.  per  ton  of  crude 
ore,  which  gain  would  increase  as  the  price  of  spelter  rose  or  the  cost  of 
smelting  diminished.  Practically,  however,  the  cost  of  smelting  the  low 
grade  ore  would  be  higher  per  ton  than  for  the  high  orrade  ore,  and  the 


MECHANICAL   CONCENTRATION    OF   ZINC    OK11S. 


percentage  of  metal  recovered  would  be  less,  so  there  probably  would  be  no 
gain  at  all.     The  table  referred  to  is  as  follows : 


Weight  of  Ore  and  Assay  in  Zinc. 

5  86  tons. 

60%  Zn. 

8  89  tons. 

45%  Zn. 

Carting  and  loading  on  cars  @  25c  
Railway  freight  @  $1  .00  
Smelting  @  9.50  

$  1-47 
5  86 
55-67 

$  2  22 

8-89 
84  46 

Totals  

$63  00 

95  57 

3  50 

4'00 

Per  cent  recovered  in  smelting  
Tons  zinc  recovered  . 

86-00 
3'01 

86-00 
3  44 

Value  @  $80  per  ton  
Cost  of  smelting  and  freight  

240-80 
63-00 

275-20 
95-57 

Margin  

177-80 

179  63 

It  is  evident  therefore  that  an  increase  of  only  10  units  in  the  recovery 
of  mineral  in  the  dressing  works  would  not  pay  for  the  extra  cost  of  smelt- 
ing the  greater  bulk  of  ore,  even  in  Kansas,  where  the  cost  of  carriage  of 
ore  to  the  smelter  is  comparatively  low.  If  the  ore  had  to  be  carried  a  long 
distance  the  comparison  would  be  still  more  unfavorable  to  the  lower  grade. 
In  other  words,  it  may  be  more  profitable  to  throw  away  a  considerable 
percentage  of  mineral  than  to  stand  the  cost  of  smelting  an  increased  quan- 
.tity  of  lower  grade  ore. 

The  figures  cited  above  are  used  to  illustrate  the  method  of  calculation 
and  are  not  intended  to  indicate  any  actual  results.  They  call  attention, 
however,  to  the  advisability  of  determining  the  efficiency  of  the  dressing 
practice  with  the  particular  kind  of  ore  which  is  being  concentrated.  If 
the  percentage  of  mineral  recovery  can  be  increased  without  reducing  the 
grade  of  the  concentrate  there  will  be  of  course  a  clear  gain  of  the  extra 
value  of  the  mineral  recovered,  less  the  additional  cost  of  dressing.  For 
example,  if  100  tons  of  ore  assaying  5%  Zn  yield  5-86  tons  of  concentrates 
assaying  60%  Zn  (70%  recovery)  and  selling  for  $25  per  ton,  the  value  of 
a  ton  of  the  crude  ore  would  be  $1465 ;  if  by  an  additional  milling  process 
0-8  ton  more  of  60%  ore  could  be  produced,  raising  the  percentage  of  recov- 
ery to  80.,  the  value  of  a  ton  of  crude  ore  would  be  increased  to  $1-667. 

SEPARATION  OF  BLENDE  AND  PYRITES. — Owing  to  the  proximities  of  the 
specific  gravities  of  blende  (3-9  to  4-1)  and  pyrite  (4-8  to  5-2)  a  simple 
separation  by  jigging  can  seldom  be  made  very  successfully.  Blende  and 
marcasite  are  even  more  difficult  to  separate  than  blende  and  pyrite,  the 
specific  gravity  of  marcasite  being  only  4-8,  Sometimes,  however,  an  ad- 
vantage can  be  gained  by  roasting  a  mixed  ore  sufficiently  to  make  the  pyrites 
less  dense  or  otherwise  alter  the  physical  conditions  of  the  two  minerals. 


256  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

A  process  of  this  nature  has  been  employed  by  the  Soeiete  Anonyme  de  la 
Vieille  Montagne  at  Ammeberg,  Sweden,  for  nearly  40  years.1  The  raw 
ore  after  hand  sorting  is  slightly  roasted  in  shaft  furnaces,  in  which  the 
ore  is  charged  with  coal  in  alternate  layers.  The  blende  remains  unal- 
tered, while  the  pyrite  crumbles,  becomes  spongy  and  porous  and  is  easily 
washed  off  by  water  in  the  subsequent  treatment.  A  similar  process  was 
introduced  at  the  works  of  the  Matthiessen  &  Hegeler  Zinc  Co.  at  Lasalle, 
111.,  when  a  mechanical  concentrating  plant  was  operated  there.  About 
1891,  W.  P.  Blake  inaugurated  the  system  in  the  Helena  mill  of  the  Wis- 
consin Lead  and  Zinc  Co.,  three  miles  west  of  Shullsburgh,  Wis.,  and  it  is 
now  practiced  on  a  small  scale  in  the  Joplin  district  in  the  treatment  of 
ores  high  in  pyrite. 

Practice  in  Wisconsin. — Blake  described  the  practice  in  Wisconsin  in  a 
paper  in  Trans.  Am.  Inst.  Eng.,  vol.  XXII.  The  sulphide  ore  of  Wis- 
consin contains  a  good  deal  of  marcasite,  together  with  some  galena,  mixed 
with  the  blende.  It  was  roasted  in  a  special  furnace,  which  had  a  circular, 
revolving  hearth,  arranged  in  the  form  of  a  series  of  concentric  annular 
steps,  on  which  the  ore  was  stirred  and  moved  forward  mechanically  by 
rakes  fixed  in  the  dome-shape  roof  of  the  furnace.  By  the  use  of  preheated 
air  for  oxidation  and  the  close  control  of  the  roasting,  which  was  possible 
thereby,  together  with  the  type  of  furnace,  Blake  succeeded  in  effecting  a 
complete  desulphurization  of  the  marcasite  without  changing  the  zinc  sul- 
phide or  even  sintering  the -galena,  the  blende  and  galena  being  drawn  from 
the  furnace  with  scarcely  a  tarnish  on  the  cleavage  surfaces  of  the  crystals. 

The  roasting  which  accomplished  that  remarkable  result  was  done  at  a 
dull  red  heat ;  so  dull  that  no  incandescence  was  visible  by  daylight.2  With 
mineral  consisting  of  about  equal  quantities  of  marcasite  and  blende,  of  the 
size  of  coarse  sand  or  grains  of  wheat,  about  20  tons  (40,000  Ib.)  could  be 
put  through  a  furnace  16  ft.  in  diameter  in  24  hours;  with  mineral  in 
which  the  marcasite  was  of  0-5  in.  size  about  10  tons  (20,000  Ib.)  could  be 
done;  the  most  desirable  mineral  was  of  0-25  in.  size.  The  roasting  caused 
the  fragments  of  marcasite  to  swell,  expand,  crack  open  and  exfoliate  in  a 
peculiar  manner,  while  there  was  only  a  slight  breaking  up  of  the  fragments 
of  blende  by  decrepitation.  Jigging  yielded  a  clean,  marketable  blende  as  a 
concentrate  and  oxides  of  iron  as  tailings.  Galena  was  obtained  in  the  first 
compartments  of  the  jigs,  and  it  was  found  that  the  heating  in  the  furnace 
caused  attached  particles  of  blende  and  galena  to  split  apart,  so  that  a 
better  separation  of  those  minerals  could  be  effected. 

1  P.  G.  Lidner,  "Ore  Dressing  in  Sweden,"   Trans.  Am.  Inst.  Min.  Eng.,  XXIV,  490. 
2W.  P.   Blake,  Trans.  Am.  Inst.  Min.  Eng.,  XXI,   948. 


MECHANICAL    CONCENTRATION    OF    ZlNC    ORES.  257 

In  carrying  out  the  process  the  ore  from  the  mines  was  first  crushed  and 
jigged  for  a  product  containing  about  25%  blende,  25%  marcasite,  and 
5  to  10%  galena,  the  remainder  being  dolomite  and  flint.  This  concentrate 
was  dried,  roasted  as  described  above,  and  rejigged,  affording  a  product  of 
which  the  best  samples  assayed  62%  Zn,  less  than  3%  Fe  and  less  than  1% 
Pb.  According  to  Blake  the  success  of  the  process  depended  upon  a  com- 
plete and  even  roasting.  Every  particle  of  marcasite  must  be  decomposed. 
Even  a  kernel  of  unchanged  marcasite  would  cause  it  to  remain  with  the 
blende.  The  outer  coating  of  oxidized  iron  might  be  broken  away  and 
washed  off,  but  the  kernel  of  unaltered  marcasite  would  not  go  over. 

Practice  at  Iserlohn. — An  analogous  process  was  once  employed  at  Iser- 
lohn,  in  Westphalia,  but  there  the  roasting  was  carried  far  enough  to  oxidize 
nearly  all  of  the  zinc  before  the  product  was  subjected  to  jigging.  In 
executing  the  process  it  was  found  that  about  3%  S  had  to  be  left  in  the 
ore,  in  order  to  preserve  a  certain  coherence  in  the  zinc  oxide.  The  scheme 
was  suggested  by  the  finely  crystalline  and  closely  banded  structure  of  the 
component  minerals,  which  would  have  necessitated  a  very  fine  crushing 
in  order  to  liberate  them.  By  the  action  of  heat,  however,  the  ore  was 
broken  along  the  planes  of  banding,  and  the  roasted  charge  was  obtained 
largely  in  the  form  of  small  tabular  pieces.  In  washing  the  loss  of  zinc  was 
heavy,  as  would  be  expected,  and  the  process  was  hardly  a  success,  although 
it  was  said  that  careful  jigging  yielded  a  fair  separation  of  the  ore  into 
marketable  products  and  the  process  was  considered  profitable  at  the  time  it 
was  practised. 

SEPARATION  CF  BLENDE  FROM  OTHER  MINERALS  BY  SIFTING. 

A  separation  of  blende  from  other  minerals  can  sometimes  be  effected  by 
sifting,  advantage  being  taken  of  their  difference  in  brittleness  or  friability, 
or  some  other  physical  property,  such  as  decrepitation  when  heated,  to  create 
a  difference  in  the  average  size  of  the  grains  of  the  various  minerals. 

Practice  at  Lintorf. — A  dry  method  of  mechanically  separating  blende 
and  pyrites  was  formerly  employed  at  the  Lintorf  mines  in  Ehenish  Prussia. 
The  mixed  concentrate  of  those  minerals  obtained  from  the  jigs  was  dried 
and  passed  through  a  Vapart  mill,  in  which  the  particles  are  pulverized 
by  centrifugal  force  against  the  circular  walls  of  the  machine,  dropping 
thence  through  a  chute  into  an  ordinary  sizing  trommel.  The  speed  of  the 
mill — usually  about  350  r.  p.  m. — was  regulated  by  experiment  so  as  to 
develop  a  velocity  in  the  movement  of  the  particles  sufficient  to  break  up 
by  impact  the  blende,  but  not  the  pyrites.  The  two  minerals  could  then  be 


258  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

separated  by  sifting,  a  middling  product  being  returned  to  the  Vapart  mill. 
The  capacity  of  the  mill  was  2-5  to  3  tons  per  hour.  In  this  manner  it  was 
possible  to  produce  a  blende  concentrate  assaying  50%  Zn.  It  was  found 
that  for  satisfactory  work  the  material  fed  into  the  mill  should  be  of  at  least 
2-5  to  3  mm.  size  and  the  best  results  were  obtainable  with  5  to  6  mm.  stuff. 
The  process  was  due  to  F.  Biittgenbach.1 

Practice  at  Oberlahnstein. — The  gravity  separation  of  blende  and  siderite 
presents  even  greater  difficulty  than  the  separation  of  blende  and  pyrites, 
inasmuch  as  the  two  minerals  are  of  almost  identical  specific  gravity,  that  of 
blende  being  3-9  to  4-1  and  that  of  siderite,  3-7  to  3-9.  At  Oberlahnstein, 
on  the  Khine,  Germany,  a  mixture  of  those  minerals  was  formerly  separated 
by  heating  to  redness  and  throwing  into  water,  whereby  the  siderite  was 
thoroughly  disintegrated  into  small  particles,  which  could  be  easily  removed 
from  the  blende  by  sifting.2 

Heusschen  Process. — The  difference  in  the  decrepitation  of  various  min- 
erals constitutes  the  principle  of  the  Heusschen  process,  which  was  described 
in  the  Comptes  Rendus  Mensuels  of  the  Societe  de  1'Industrie  Minerale  for 
1894,  p.  98.  It  is  assumed  that  eleavable  minerals  are  more  likely  to  de- 
crepitate than  massive  and  that  each  mineral  will  have  its  own  temperature 
of  maximum  decrepitation,  whence  mixed  minerals  of  the  same  size,  if 
treated  for  the  decrepitation  of  one  of  them,  may  be  separated  by  sifting. 
To  accomplish  that,  a  metal  table  is  suspended  at  an  inclination  of  about 
12°  over  a  grate  fire.  The  table  is  jarred  lengthwise  by  a  cam,  which  causes 
the  mineral  to  travel  downward  over  the  end,  whence  it  goes  to  a  screen  for 
separation.  In  the  experiments  a  furnace  was  used,  which,  in  10  hours,  put 
through  (at  a  temperature  of  250°  C.)  1,526  kg.  of  blende-galena-barite- 
schist  ore  of  1  to  3  mm.  size,  assaying  8%  Pb  and  23-3%  Zn,  yielding  a 
product  of  1,005  kg.,  which  assayed  16-4%  Pb  and  29-9%  Zn;  of  the  barite 
present  in  the  original  ore  31%  went  into  the  tailings,  which  assayed  only 
.2%  of  the  metals. 

MAGNETIC  SEPARATION. 

The  separation  of  blende  and  calamine  from  other  minerals,  irrespective 
of  specific  gravity,  is  accomplished  with  great  success  by  the  aid  of  mag- 
netism; since  the  discovery  of  Wetherill,  this  has  been  done  even  with  min- 
erals which  display  no  marked  magnetic  properties  and  cannot  be  converts 
into  magnetic  forms,  for  example,  certain  kinds  of  blende  can  be  separat( 
thus  from  both  pyrite  and  galena.  The  mixed  sulphide  ore  of  Broken  Hill, 

1  School  of  Mines  Quarterly,  III,  p.  55. 

a  Kunhardt,    Ore   Dressing   in    Europe,    p.  103. 


MECHANICAL    CONCENTRATION    OF   ZINC    ORES.  259 

X.  S.  W.,  and  of  Leadville  and  Kokomo,  Colo.,. has  been  treated  successfully 
in  that  manner.  Both  the  Wetherill  and  the  simple  magnetic  processes 
of  separation  have  undoubtedly  a  great  future,  although  inasmuch  as  in 
plant  and  performance  they  are  more  costly  than  ordinary  gravity  separa- 
tion they  will  be  probably  employed  as  an  accessory  to  the  latter  process 
rather  than  as  a  substiute  for  it.  For  convenience,  this  subject  may  be 
considered  under  the  captions  "Separation  of  Strongly  Magnetic  Minerals'" 
and  "Separation  of  Feebly  Magnetic  Minerals." 

Separation  of  Strongly  Magnetic  Minerals. 

Iron  sulphide,  carbonate  and  sesquioxide  may  under  certain  conditions 
be  converted  into  the  magnetic  oxide,  Fe304,  in  which  form  it  is  easily  at- 
tracted by  the  magnet  and  thereby  may  be  separated  from  compounds  of 
zinc,  all  of  which  are  non-magnetic,  or  at  least  only  feebly  magnetic.  Pro- 
cesses depending  upon  that  principle  were  first  applied  many  years  ago, 
perhaps  as  early  as  1855.  Similarly,  iron  bisulphide  may  be  changed  into 
magnetic  sulphide.  The  conversion  of  non-magnetic  iron  minerals  into  the 
magnetic  form  requires  considerable  care  and  many  failures  have  been  due 
undoubtedly  to  ignorance  of  the  precise  conditions. 

Conversion  of  Iron  Bisulphide  into  Magnetic  Sulphide. — The  reduction 
of  iron  bisulphide  to  the  magnetic  subsulphide  has  been  suggested  by  Eustis 
and  Howe  among  others,1  but  experiment  has  shown  this  to  be  a  very  delicate 
operation  and  it  has  never  yet  been  put  in  practice  on  a  working  scale.  It  is 
effected  by  moderately  heating  pyrite,  when  the  change  expressed  by  the 
following  equation  takes  place : 

3FeS2=Fe3S4+2S 

G.  M.  Gouyard,  of  Denver,  Colo.,  has  published2  results  of  experiments 
on  this  subject,  showing  that  in  roasting  a  mixture  of  pyrite,  blende  and 
galena  for  magnetic  sulphide  of  iron  the  magnetic  concentrates  run  lower 
in  lead  and  zinc  than  when  magnetic  oxide  is  produced. 

Conversion  of  Ferric  Oxide  into  Magnetic  Oxide. — The  production  of 
magnetic  oxide  of  iron,  Fe304,  is  effected  by  carbon  according  to  the  follow- 
ing reactions : 

6Fe203+C=4Fe304+C02 

or  the  ferric  oxide  may  be  reduced  first  to  ferrous  oxide,  and  the  latter 
converted  to  magnetic  oxide  by  combination  with  an  atom  of  oxygen  from 

1  Trans.  Am.  Inst.  Min.    Eng.,  X,  305.  *  Proc.  Colorado   Scientific  Society,   1897. 


260  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

the  air,  which  is  known  to  take  place  when  FeO  is  heated  to  redness  in  the 
air,  the  reactions  being  expressed  thus  :* 


3FeO+0=Fe304 

When  siderite  is  calcined  it  is  decomposed  according  to  the  reaction, 
FeC03:=FeO+C02 

and  the  molecule  of  FeO  is  subsequently  converted  to  Fe304  by  taking 
oxygen  from  the  air.  The  roasted  carbonate  is  always  strongly  magnetic, 
but  in  execution  of  the  process  the  temperature  must  be  regulated  carefully 
to  avoid  sintering  the  ore,  which  because  of  the  fusibility  of  ferrous  oxide 
and  silica  may  easily  happen.  According  to  Le  Chatelier2  the  decomposition 
of  ferrous  carbonate  takes  place  at  800°  C. 

The  bisulphide  of  iron  may  be  changed  into  the  magnetic  oxide  if  it  be 
roasted  carefully  at  dull  red  heat.  Practically,  however,  it  is  difficult  to 
obtain  all  of  the  iron  in  that  form  and  it  is  generally  necessary  after  the 
sulphur  has  been  removed  to  introduce  some  carbonaceous  matter  so  as  to 
reduce  the  ferric  oxide  to  magnetic  oxide.  When  the  iron  is  present  orig- 
inally as  ferric  oxide,  as  in  limonite  ore,  a  similar  reduction  by  carbon  is 
necessary.  Siderite  on  the  other  hand  is  converted  into  magnetic  oxide  by 
a  simple  heating.  The  last  process,  not  requiring  so  much  delicacy  in 
manipulation,3  has  found  more  general  application. 

Practice  at  Monteponi.  —  At  Monteponi,  Sardinia,  an  ore  consisting  of 
hemimorphite  and  limonite,  with  a  gangue  of  dolomite  and  clay,  is  separated 
magnetically  in  a  plant  designed  by  E.  Ferraris,  director-general  of  the 
Societa  di  Monteponi.  The  ore  is  first  roasted  in  a  revolving  cylinder  fur- 
nace with  the  addition  of  2  to  3%  coal  slack  to  reduce  the  ferric  oxide  to 
magnetic  oxide.  The  product  after  cooling  is  elevated  to  a  trommel,  which 
separates  it  into  six  classes  of  1,  2,  3,  4,  5  and  6  mm,  size,  respectively, 
which  are  delivered  to  corresponding  magnetic  machines.  The  design  of 
the  latter  is  shown  in  Fig.  27.  They  consist  essentially  of  a  horseshoe 
electro-magnet,  beneath  the  poles  of  which  travel  two  belts,  the  directions  of 
the  latter  being  at  right  angles.  The  poles  of  the  magnet  are  50  mm.  long 

1  These  reactions  are  expressed  merely  as  oxide,  by  carbon  or  carbon  monoxide,  when 
typical,  the  reduction  not  being  necessarily  It  is  mixed  with   zinc   oxide,   carbonate   or 
effected  by  carbon,   but  perhaps  by   carbon  silicate,   it  is  necessary  not  only  to  obtain 
monoxide  or  carbonic  monoxide  and  carbon  the  proper  reduction  of  the  ferric  oxide  but 
together,  also  to  avoid  reducing  the  zinc  compounds, 

2  Thonind.  Ztg.,  1886,  p.  429.  which  would  lead  to  a  loss  of  zinc  by  vola- 
*  In    attempting    the    reduction    of    ferric       tilization. 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES. 


261 


and  have  an  elliptical  cross-section,  of  which  the  axes  are  0-06  X 0-15  nu 
They  are  wound  with  copper  wire  of  0-5  sq.  mm.  section.  The  machine 
shown  in  Fig.  27  was  an  experimental  one,,  and  those  finally  installed  had 
two  magnets  over  the  lower,  or  feed,  belt,  and,  of  course,  a  second  upper,  or 


FIG.  27. — THE  FERRARIS  MAGNETIC  SEPARATOR: 

discharge,  belt,  to  correspond  to  the  second  magnet.  These  machines  re- 
quire 100  watts  of  current — i.  e.,  two  amperes  under  a  tension  of  50  volts. 
In  the  following  description  the  feed  belt  is  designated  as  a,  and  the  dis- 
charge belt  as  I,  which  letters  are  not  shown  in  the  engraving. 


UNIVERSITY 

OF 


262  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

The  Monteponi  plant  comprises  six  separators.  The  sized  ore  is  delivered 
on  the  belt  a,  which  carries  it  under  the  poles  of  the  magnets  at  a  distance 
of  20  to  50  mm.,  the  distance  being  adjustable.  The  minimum  speed  of 
this  belt  is  0-5  in.  per  second.  The  belts  &,  which  are  interposed  between  a 
and  the  poles  of  the  magnets,  prevent  the  magnetic  particles  from  becoming 
attached  to  the  latter  and  carry  them  out  of  the  line  of  travel  of  belt  a, 
dropping  them  as  soon  as  out  of  the  magnetic  field.  The  first  magnet  over 
belt  a  picks  out  the  finer  and  more  highly  magnetic  particles,  which  are 
delivered  by  belt  b  as  a  clean  product.  The  second  picks  out  a  mixed 
product  of  larger  pieces,  which  are  pulverized  and  reworked  over  the  ma- 
chines. The  machines  are  capable  of  adjustment  by  varying  the  magnetic 
force,  or  the  distance  between  the  magnets  and  the  belt,  the  latter  being 
effected  by  means  of  small  rollers  under  the  belt.  In  the  preliminary  ex- 
periments a  single  magnet  machine,  like  that  shown  in  Fig.  27,  was  found 
able  to  separate  0-2  to  0-3  cu.  m.  of  ore  per  hour.  The  six  double  machines 
as  installed  treat  on  the  average  about  1,000  kg.  of  calcined  ore  per  hour. 

The  ore  treated  assays  22%  Zn  before  calcination:  30%  Zn  after  calcina- 
tion. One  metric  ton  of  ore  yields  about  667  kg.  of  mineral  containing  40% 
Zn  and  333  kg.  of  iron  ore  containing  from  4  to  10%  Zn.  The  former 
product  is  treated  on  a  jig,  wherein  the  burned  dolomite  slakes  and  is  washed 
off,  together  with  the  excess  of  reduction  coal,  while  the  calamine  passes 
through  the  sieve  and  is  recovered  from  the  hutch  as  a  product  assaying 
48%  Zn,  its  weight  being  50%  that  of  the  roasted  ore.1  Of  the  300  kg.  of 
zinc  contained  in  a  ton  of  roasted  ore  there  is  consequently  a  recovery  of 
240  kg.,  or  80%,  which  may  be  considered  a  favorable  result. 

SEPARATION  OF  SIDERITE  AND  BLENDE. — The  separation  of  siderite  from 
blende  by  magnetism  was  done  in  the  Lill  dressing  works  at  Przibram,  Bo- 
hemia, as  early  as  the  decade  1870-1880.  The  apparatus  employed  was  de- 
scribed in  Trans.  Am.  Inst.  Min.  Eng.,  IX,  420.  A  similar  separation  of 
siderite  and  oxidized  zinc  ore  was  practiced  in  Spain  at  an  equally  early  date, 
machines  capable  of  treating  one  to  two  tons  of  ore  per  hour,  devised  by 
Doctor  Werner  Siemens,  being  employed.2  The  installation  at  Friedrichs- 
segen,  near  Ems,  in. Nassau,  was  also  made  as  early  as  20  years  ago.  Until 
recently  it  was  probably  the  most  important  place  where  the  magnetic 
separation  of  blende  and  siderite  was  effected  by  the  calcination  method,  but 
the  latter  has  now  been  supplanted  there  by  the.  Wetherill  process. 

Practice  at  Friedrichssegen. — The  ore  treated  at  Friedrichssegen  is  a  mill 

1E.  Ferraris,  Oest.  Zts.,  1898,  p.  347.  be  made  also  to  a  paper  on  magnetic  sepa- 

1  Werner    Siemens.    Gesammelte    Abhand-       ration  by  G.  Prus,  in  Le  Genie  Civil, 
lungen,  1881,  p.  537  et  seq.      Reference  may        XVII.   3.°>7. 


MECHANICAL   CONCENTRATION    OF   ZINC    ORES. 


product  assaying  from  11  to  15%  Zn  (in  the  form  of  blende)  and  18  to 
23%  Fe  (in  the  form  of  siderite).  This  was  heated  to  redness  in  a  me- 
chanical furnace  of  the  McDougall  type,  which  put  through  from  20,000 
to  25,000  kg.  of  ore  (according  to  the  size  of  the  particles)  in  24  hours, 
with  a  coal  consumption  of  1,200  kg.  The  plant  comprised  two  furnaces, 
each  of  which  required  the  attention  of  one  man,  who  also  trammed  the 
calcined  ore  to  the  cooling  floor.  When  the  ore  had  cooled  to  50°  C.,  or 
lower,  it  was  elevated  to  a  trommel,  which  divided  it  into  sizes,  namely, 
larger  than  4  mm.,  2  to  4  mm.  and  smaller  than  2  mm.  The  stuff  larger 
than  4  mm.,  which  was  due  to  fritting  together  of  particles  during  the  cal- 
cining, went  to  a  set  of  rolls,  by  which  it  was  reduced  to  4  mm.,  whence  it 
was  raised  again  to  the  sizing  screen ;  the  stuff  from  2  to  4  mm.  in  size  and 
smaller  than  2  mm.  fell  into  separate  bins,  whence  it  was  drawn  to  the  pri- 


Middliags 


FIG.  28. — ARRANGEMENT  OF  MAGNETIC  SEPARATORS  AT  FRIEDRICHSSEGEN, 

GERMANY. 

I  nary  magnetic  separators.  There  were  12  of  the  latter  arranged  in  three 
groups  of  four  each,  the  four  machines  of  each  group  being  set  in  pairs  and 
the  pairs  in  series.  The  arrangement  of  the  four  machines  constituting  a 
group  is  shown  in  Fig.  28.  Two  groups  took  the  coarser  mineral  and  two 
the  finer.  The  ore  diverted  to  a  group  was  divided  equally  between  machines 
A  and  B,  which  made  two  products,  one  enriched  in  zinc  and  the  other  en- 
riched in  iron.  The  iron  product  of  both  machines  was  led  to  D  and  the 
zinc  product  to  C.  The  two  lower  machines  made  a  zinc  product  with  38  to 
42%  Zn  and  6%  Fe  at  the  most,  a  mixed  product,  and  an  iron  product, 
which  still  contained  6  to  8%  Zn.  The  mixed  product  was  retreated  by  a 
group  of  two  machines.  The  iron  product  went  to  another  group  of  four 


{4 

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P3 
P4 

02 

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3 

PW 

os" 
o 


MECHANICAL   CONCENTRATION    OF   ZINC   ORES. 


265 


machines,  which  yielded  a  final  product  containing  40%  Fc  and  3  to  4%  Zn; 
that  represented  the  entire  loss  of  zinc  in  the  process. 
It  will  be  observed  that  the  plant  comprised  18  separators,  of  which  12 


Horizontal  Section 

FIGS.  30  AND  31. — CALCINING  FURNACE  USED  AT  FRIEDRICHSSEGEN. 

were  employed  in  making  the  primary  separation  and  six  in  reworking  be- 
tween products.  The  general  arrangement  of  the  plant  is  shown  in  the 
accompanying  engraving,  Fig.  29,  which  will  be  readily  understood  from  the 
foregoing  description. 


266  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

Calcining  Furnace. — The  calcining  furnace  used  at  Friedrichssegen  re- 
quires no  extended  description,  since  it  differs  from  the  Herreshoff  furnace 
and  others  of  the  McDougall  type  only  in  dimensions  and  structural  details. 
It  has  two  series  of  five  superimposed  hearths,  which  are  about  6  ft.  in 
diameter.  The  vertical  shaft,  which  carries  the  stirring  arms,  is  protected 
from  the  heat  inside  the  furnace  by  an  enclosing  tube,  and  is  driven  by  a 
worm  gear  at  its  upper  end.  In  each  hearth-room  there  is  a  stirring  arm 
which  moves  forward  the  ore.  The  latter  falls  on  the  uppermost  hearth 
at  its  periphery  and  is  plowed  toward  the  center,  where  it  falls  through  a 
hole  to  the  second  hearth,  on  which  it  is  plowed  toward  the  periphery,  and 
so  on,  being  discharged  from  the  lowest  hearth  into  a  car  standing  to 
receive  it.  The  furnace  is  fired  from  a  grate,  whence  the  flames  pass  over  the 
hearths  in  the  direction  of  the  arrows,  escaping  through  a  dust  chamber  to 
the  chimney.  The  speed  of  the  plows  is  regulated  according  to  the  size  of 
the  ore  particles.  The  admission  of  air  into  the  furnace  is  governed  so  as 
to  prevent,  so  far  as  possible,  the  formation  of  ferric  oxide  instead  of 
magnetic  oxide. 

The  Wenstrom  Separator. — The  magnetic  separators  employed  at  Fried- 
richssegen, which  are  shown  in  Figs.  32  to  35,  were  of  the  Wenstrom  type 
and  very  simple  in  construction.  A  wooden  frame  supports  a  stationary  axis 
1),  to  which  is  fastened  a  casting  wound  with  copper  wire  so  as  to  form  four 
electromagnets,  the  wires  for  the  connection  of  the  latter  passing  through 
the  axis  &,  which  at  each  end  is  bored  for  a  third  of  its  length.  The  magnets 
which  are  stationary  in  the  position  shown  in  the  accompanying  engraving, 
Fig.  33,  are  surrounded  by  a  brass  drum,  on  the  exterior  of  which  brass 
flanges  are  brazed  on  parallel  with  its  central  axis.  The  drum  is  rotated  in 
the  direction  of  the  arrow  by  means  of  the  pulley  g,  while  a  pulley  Jif  on 
the  opposite  side,  transmits  motion  to  the  shaking  tray  e,  which  receives  ore 
from  the  hopper  d  and  presents  it  to  the  drum  in  a  thin,  even  sheet.  The 
space  between  the  edge  of  the  tray  and  the  drum  is  adjustable.  In  operation, 
the  magnetic  particles  are  attracted  to  the  surface  of  the  drum,  where  they 
are  held  so  long  as  in  the  magnetic  field,  being  thence  carried  over  into  a 
separate  bin,  the  flanges  preventing  them  from  falling  back.  The  non- 
magnetic particles  fall  directly  from  the  edge  of  the  tray  into  a  bin.  The 
capacity  of  a  single  machine  is  from  300  to  500  kg.  per  hour.  The  drum 
makes  36  r.  p.  m.  and  the  shaking  tray  from  180  to  200  throws  per  minute. 
The  power  required  is  0-125  h.  p.  and  the  electric  current  about  325  watts 
per  machine.  The  Friedrichssegen  plant  comprised  five  dynamos,  each  of 
which  delivered  20  to  25  amperes  of  65  volts.  One  man  attended  to  the 
entire  plant  of  separators. 


MECHANICAL    CONCENTRATION    OF    ZINC    OKES. 


267 


According  to  C.  Blomeke,1  the  Wether  ill  machines,  which  have  been  in- 
troduced at  Friedrichssegen,  have  been  found  to  do  twice  the  work  of  the 
Wenstrom  machines,  while  they  have  the  further  advantage  of  occupying 
less  room  and  not  requiring  the  ore  to  be  roasted. 

SEPARATION  OF  FRANKLINITE  AND  WILLEMITE. — In  1892,  Mr.  G.  G.  Con- 
vers,  superintendent  of  the  Lehigh  Zinc  Co.'s  works  at  South  Bethlehem, 
Penn.,  installed  there  an  experimental  plant  of  Wenstrom  separators  for  the 
treatment  of  the  mixed  ore  of  Xew  Jersey.  The  ore,  which  consisted  of 


FIGS.  32  TO  35. — THE  WENSTROM  MAGNETIC  SEPARATOR. 

51-92%  franklinite,  31-58%  willemite,  12-67%  calcite,  0-52%  zinkite,  and 
3-31%  tephroite  and  other  silicates,  was  first  crushed  to  pass  a  10-mesh 
sieve,  and  was  then  mixed  with  20%  of  its  weight  of  anthracite  coal  (buck- 
wheat size)  and  passed  through  a  brick-lined  revolving  cylinder,  heated  by 
gas  from  a  Taylor  producer.  The  heat  of  the  furnace  was  regulated  so 

'Oest.  Zts.,  1898,  p.  147. 


268  PRODUCTION   AND   PROPERTIES    OF   ZINC. 

that  the  ore  issued  from  it  at  a  bright  red.  The  hot  ore  was  conveyed  into 
a  revolving  cooler,  around  the  surface  of  which  cold  water  was  sprayed. 
After  cooling,  it  was  sifted  to  remove  unburned  coal  (which  was  used  sub- 
sequently on  the  grates  of  the  zinc  oxide  furnaces,,  whereby  the  small  quan- 
tity of  zinc  retained  by  it  was  recovered),  while  the  ore  itself  was  collected 
in  bins,  whence  it  was  led  to  three  Wenstrom  magnetic  separators,  arranged 
in  series.  These  machines  were  run  so  as  to  make  a  clean  non-magnetic 
product  of  willemite,  zinkite,  calcite  and  silicates,  and  a  magnetic  product 
consisting  chiefly  of  franklinite.  The  latter  was  sent  directly  to  the  oxide 
furnaces;  the  former  to  jigs  and  tables  by  which  the  calcite  and  silicates 
were  removed.  The  final  products  were:  (I)  magnetic,  franklinite  and 
willemite,  assaying  about  29-66%  ZnO,  37-20%  Fe,  and  9-34%  Mn;  (II), 
non-magnetic,  heavy  minerals,  chiefly  willemite,  assaying  from  46-38%  Zn, 
3-76%  Fe,  and  6-68%  Mn.  to  48%  Zn,  2%  Fe,  and  7%  Mn.;  and  (III) 
non-magnetic,  light  minerals,  chiefly  calcite  and  silicates.  The  process 
gave  good  results ;  but  the  cost  of  the  roasting  and  the  uncertainty  of  pro- 
ducing a  uniformly  magnetic  product  led  to  further  experiments,  from 
which  a  direct  separation  of  the  minerals,  without  previous  roasting,  was 
developed  by  Mr.  J.  P.  Wetherill,  whose  process  is  described  in  the  follow- 
ing section  of  this  chapter. 

Separation  of  Feebly-Magnetic  Minerals. 

It  has  been  shown  by  Faraday,  Pliicker,  Wicdemann  and  others  that  mag- 
netism is  an  inherent  property  of  all  substances ;  which  are  either  attracted 
or  repelled  by  the  poles  of  a  magnet,  though  in  most  substances  the  mani- 
festation of  that  property  is  exceedingly  feeble.  Those  substances  which  are 
attracted  are  said  to  be  paramagnetic;  those  which  are  repelled  are  diamag- 
netic.  The  paramagnetics  show  a  wide  variation  in  magnetic  intensity;  the 
diamagnetics  show  but  slight  deviation  in  intensity  as  compared  with  air, 
which  is  the  neutral  substance.  Taking  air  as  unity,  the  diamagnetic  in- 
tensity of  bismuth  is  only  0-99982  and  bismuth  is  the  most  diamagnetic  sub- 
stance known ;  on  the  other  hand,  among  the  paramagnetics,  if  the  attracta- 
bility  of  steel  be  assumed  as  100,000,  that  of  magnetite  is  as  high  as  65,000, 
while  sicleritc  is  only  120,  hematite  93  to  43  and  limonite  72  to  43.  There 
is  little  data  as  to  the  relative  magnetic  attractability  of  various  minerals,1 
and  in  any  case  such  figures  would  not  be  of  great  value  owing  to  the  vari- 
able influence  of  impurities. 

1  Pliicker  has  given  the  following  data  as  is  valued  at  100,000:  magnetite,  40,227; 
to  the  magnetic  permeability  of  various  slderite.  761 ;  hematite,  714 ;  limonite,  296 ; 
minerals  compared  with  metallic  iron,  which  haussmannite  (Mn3O4),  167. 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES.  269 

For  practical  purposes  it  may  be  considered  that  all  minerals  containing 
manganese  and  iron,  even  garnet,  are  paramagnetic,  except  pyrite,  which  if 
paramagnetic  is  so  feebly  so  that  it  cannot  be  separated  from  the  diamag- 
netics,  while  quartz,  calcite,  dolomite  and  the  zinc  minerals  (except  f rank- 
Unite  and  ferruginous  blende)  are  diamagnetic.  Pure  blende  is  absolutely 
diamagnetic,  while  ferruginous  blende  is  more  or  less  paramagnetic.  This 
difference  is  of  great  practical  importance.  In  effecting  a  separation  of 
pure  blende  from  pyrite,  as  must  be  done  with  some  of  the  Joplin  ore,  it  is 
necessary  to  subject  it  to  a  preliminary  roasting,  because  both  the  blende 
and  the  pyrite  are  diamagnetic.  The  blende  of  Leadville,  Colo.,  on  the 
other  hand  is  ferruginous  and  sufficiently  paramagnetic  to  enable  it  to  be 
removed  from  the  pyrite,  which  is  mixed  with  it,  without  any  preliminary 
treatment.  According  to  Langguth1  the  magnetic  permeability  of  blende 
varies  according  to  its  tenor  of  FeS  or  MnS. 

Although  the  weak  magnetism  of  many  minerals  besides  magnetite  and 
pyrrhotite  was  common  knowledge  for  many  years,  it  remained  for  J.  Price 
Wetherill,  general  manager  of  the  Lehigh  Zinc  Co.,  of  South  Bethlehem, 
Penn.,  to  invent  a  practical  machine  developing  such  high  magnetic  inten- 
sity that  advantage  could  be  taken  of  this  property  for  the  commercial  sepa- 
ration of  various  minerals,  which  either  could  not  previously  be  converted 
into  magnetic  forms  at  all  or  could  be  thus  converted  only  with  difficulty 
and  by  delicate  manipulation.  Although  the  Wetherill  machines  are  applic- 
able to  a  great  variety  of  metallurgical  processes,  they  were  designed  pri- 
marily for  the  treatment  of  the  mixed  zinc  ore  of  New  Jersey,  and  in  accom- 
plishing that  to  perfection,  besides  furnishing  a  means  whereby  the  mixed 
sulphide  ore  of  Broken  Hill  and  Leadville  can  be  separated,  and  whereby 
iron  can  be  largely  removed  from  any  zinc  ore,  they  have  constituted  one  of 
the  most  important  contributions  to  the  metallurgy  of  zinc  in  recent  years. 
Their  efficiency  is  so  great  that  they  are  bound  to  be  used  in  any  new  instal- 
lation for  the  separation  of  blende  and  siderite,  or  calamine  and  limonite, 
instead  of  the  simple  magnetic  machines  described  in  the  first  section  of 
this  chapter. 

THE  WETHERILL  SEPARATOR. — The  Wetherill  magnetic  separators2  are 
designed  on  the  principle  of  developing  a  peculiarly  high  magnetic  power, 
sufficient  to  act  on  minerals  of  such  low  magnetic  permeability  as  limonite, 
hematite,  siderite,  etc.  They  were  made  originally  of  two  types:  (1)  espe- 

1  Fascicule    de    1'Electrochemie.    No.    23,  Wetherill   Separating  Co.   of  New  York,  In 

Dec.  7,  1899.  the  United  States  and  Canada;  and  by  the 

'United     States     patents,     Nos.     555,792  Metallurgische    Gesellschaft,    of    Frankfurt 

(March    3,    1896)    and    555,794    (March    3.  am  Main,  in  foreign  countries. 
1896).     These  patents  are  controlled  by  the 


270 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


cially  for  the  treatment  of  fine  ores  and  those  from  which  rich  magnetic 
heads  are  particularly  sought ;  and  ( 2 )  especially  for  comparatively  coarse 
ores  and  those  from  which  a  clean  non-magnetic  product  is  desired. 


FIGS.  36  AND  37. — PLAN  AND  ELEVATION  OF  WETHERILL  MAGNETIC 
SEPARATOR,  TYPE  No.  1. 

The  first  type  of  machine  is  shown  in  Figs.  36,  37  and  38.  This  machine 
consists  essentially  of  two  magnetic  cores  and  bobbins  AA,  and  four  pole 
pieces,  EEEE,  which  are  pointed  in  the  manner  shown  and  are  adjustable  by 
the  bolts  C,  so  that  they  may  be  moved  nearer  together  or  further  apart,  as 
may  be  desired.  For  substances  of  very  low  magnetic  permeability  two  of 


MECHANICAL   CONCENTRATION    OF   ZINC    ORES. 


271 


the  pole  pieces  are  dispensed  with  and  a  solid  yoke  is  used  instead ;  for  sub- 
stances of  higher  magnetic  permeability,  such  as  garnet,  f  ranklinite,  siderite, 
etc.,  the  yoke  may  be  removed  and  two  pole  pieces  substituted  for  it, 
as  shown.  A  belt  D,  shown  in  Figs.  36  and  38,  driven  in  the  direction 
of  the  arrow  by  the  pulley  E,  shown  in  Fig.  36,  passes  between  the 
negative  and  positive  poles.  The  ore  is  fed  from  a  hopper,  F,  by  means  of  a 
feed  roller  6r,  upon  a  belt,  H,  which  carries  it  in  a  layer,  say  %  to  3/16  in. 
thick,  to  and  over  the  pulley  J,  which  is  of  a  small  diameter  and  rotates  on 
a  brass  axle  K,  so  arranged  that  it  may  be  raised  or  lowered  by  the  adjustable 
hearing  P.  The  ore  is  thus  delivered  in  close  proximity  to  the  space  be- 
tween the  poles  and  the  magnetic  particles  are  withdrawn  and  lifted  into 
the  highly  intensified  field  existing  at  that  point.  They  are  removed  by  the 


FIG.  38. — SECTION  OF  POLE  PIECES  OF  WETHERILL  MAGNETIC  SEPARATOR. 

An  enlarged  section  from  Fig.  36,  showing  the  arrangement  of  the  pole  pieces  and  the 

feed  belt. 

horizontal  belt  D,  and  carried  into  a  receptacle  L.  The  non-magnetic  tails 
fall  from  the  belt  H  into  the  receptacle  M.  The  intensity  of  the  magnetic 
attraction  can  be  accurately  adjusted  by  changing  the  distance  of  the  feed 
belt  from  the  pole  points,  or  by  changing  the  distance  between  the  pole 
points,  or  by  changing  the  amperage  of  the  current. 

In  machines  of  the  second  type,  shown  in  Figs.  39  and  40,  the  magnetic 
particles  adhere  to  the  feed  belt  as  it  rounds  the  pole  points,  while  the  non^ 
magnetic  material  falls  away  from  it.  The  machine  consists  of  magnets 
with  cores  and  bobbins  Af  yokes  B,  pointed  pole  pieces  Cf  belts  D  passing 
around  the  pole  pieces  in  the  manner  shown,  ore  hoppers  E,  feed 
rollers  F,  and  chutes  G,  which  rfrVvrT.  ^o  0™  in  n  thin  IRVPT  on  the  belts  D. 


272 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


The  belts  travel  in  the  direction  of  the  arrows  and  deliver  the  ore  directly 
into  the  opening  between  the  pole  pieces,  the  distance  apart  of  which  is  ad- 


•  iinii 

Section  through  "B" 

FIGS.  39  AND  40. — SIDE  ELEVATION  AND  HORIZONTAL  SECTION  OF 
WETHERILL  MAGNETIC  SEPARATOR,  TYPE  No.  2. 

justable.  Two  shutters  HH,  one  beneath  the  point  of  each  pole  piece,  are 
justable  so  that  the  magnetic  particles  which  adhere  slightly  to  the  pole  pieces 


MECHANICAL    CONCKN'TUATIOX    OF    ZINC    ORES.  273 

are  carried  to  one  side  by  the  moving  belts  D  into  the  receptacles  MM  on 
either  side  of  the  shutters,  while  the  non-magnetic  fall  through  the  space 
between  the  shutters  and  into  the  receptacle  L.  The  separation  may  be 
regulated  by  varying  the  position  of  the  shutters,  the  speed  of  the  belts,  the 
distance  between  the  pole  points,  or  the  volume  of  current. 

The  machines  described  above  were  the  earlier  forms,  as  illustrated  by 
Messrs.  H.  A.  J.  Wilkens  and  H.  B.  C.  Nitze  in  Trans.  Am.  Inst.  Min.  Eng., 
XXVI,  351  et  seq.  These  have  been  superseded  by  others,  which  although 
operating  on  the  same  general  principle  show  considerable  improvement  in 
their  mechanical  features.  The  main  credit  for  these  improvements  is  due 
to  Mr.  Lewis  G.  Eowand  and  Mr.  Max  Schiechel,  the  former  having  been 
connected  with  the  exploitation  of  the  machines  in  America  and  the  latter 
having  been  in  charge  of  the  operations  in  foreign  countries.1 

The  machines  now  in  use  may  be  divided  into  two  types:  (1)  those  in 
which  the  magnetic  particles  are  lifted  and  carried  away  from  the  non- 
magnetic; and  (2)  those  in  which  the  course  of  the  moving  ore  is  influenced 
magnetically  in  such  a  way  as  to  carry  the  various  ingredients  in  separate 
directions,  according  to  their  magnetic  permeability. 

The  most  highly  developed  machine  of  the  first  class  is  illustrated  in  Fig. 
43,  while  its  method  of  operating  is  shown  diagrammatically  in  Figs.  41 
and  42.  This  has  a  horizontal  carrying  belt  which  passes  between  the  poles 
of  a  pair  of  magnets,  as  represented  in  Fig.  42,  the  pointed  pole  pieces  PP1 
of  the  upper  magnet  M  being  placed  close  to  the  flat  pole  pieces  LL'  of  the 
lower  magnet  M'.  The  discharge  belts  T  and  T'  pass  around  the  poles  of 
the  upper  magnet,  as  shown  in  Fig.  41.  In  Fig.  42  only  one  pair  of  mag- 
nets is  shown,  but  generally  this  type  is  arranged  with  two  or  three  pairs, 
the  latter  number  being  shown  in  Fig.  43.  The  standard  machine  of  this 
type  has  an  18  in.  carrying  belt.  The  current  employed  for  three  pairs  of 
magnets  is  approximately  5+15+30  amperes  at  110  volts;  the  mere  driving 
of  the  belts  does  not  require  more  than  0-5  h.  p.  The  capacitv  of  the  ma- 
chine ranges  from  600  Ib.  to  12,000  Ib.  per  hour.  Such  a  machine  costs 
$3,850  f.  o.  b.  Xew  York,  besides  which  the  owners  of  the  patents  demand  a 
certain  royalty  per  ton  of  product  for  the  license  to  use  it. 

A  machine  of  the  second  class,  which  is  used  in  Europe  and  Australia 
for  ores  that  are  only  slightly  magnetic,  is  illustrated  in  Fig.  44.  In  this 
there  are  three  magnetic  coils  and  pole  pieces.  The  pole  point  P,  which 
does  the  active  work  of  separation,  is  of  opposite  polarity  to  the  points  P1 
and  P2.  Around  the  pole  point  P  passes  a  thin  linen  belt  F,  on  which  the 
ore  is  fed  from  the  hopper  H  by  means  of  the  feed  roller  P.  When  the  ma- 

*  H.  A.  T.  Wilkens,  The  Mineral  Industry,  X.  776. 


274 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


terial  reaches  the  pole  point  P,  the  magnetic  particles  adhere  to  the  feed 
belt  F  as  it  rounds  the  point,  while  the  non-magnetic  are  thrown  off  by  the 
momentum  imparted  to  them  by  the  belt.  By  means  of  the  shutter  Sf  which 
can  be  adjusted  with  a  small  set  screw,  the  two  grades  of  ore  are  accurately 
separated.  This  machine  operates  successfully  on  materials  of  very  slight 
magnetic  permeability  at  the  expense  of  a  comparatively  low  magnetic  cur- 
rent, it  being  only  necessary  to  hold  the  material  for  a  moment  against  the 
pole  point  as  compared  with  the  necessity  of  actually  lifting  the  materials  in 
machines  of  the  type  shown  in  Figs.  41  to  43.  There  is  some  wear  of  the 
feed  belt  while  rounding  the  pole  point  P,  as  well  as  that  of  the  pole  point 
itself.  The  proper  adjustment  of  the  shutter  S,  as  well  as  that  of  the  whole 
machine,  is  a  somewhat  delicate  matter,  and  its  use  is  advisable  only  when 


FIGS.  41  AND  42. — MODERN  FORM  OF  WETHERILL  SEPARATOR  WITH 

HORIZONTAL  BELT. 

the  ore  is  so  slightly  magnetic  that  it  is  impossible  to  make  satisfactory 
separation  with  the  machine  shown  in  Figs.  41  to  43. 

A  three  pole  machine  which  combines  certain  of  the  features  of  the  two 
types  described  above  has  been  used  in  Europe  to  a  considerable  extent.  In 
this  the  feed  belt  passes  around  a  roller  below  the  field  of  the  three  magnets, 
which  are  themselves  surrounded  by  a  take-off  belt.  As  the  ore  reaches  the 
magnetic  field,  the  non-magnetic  material  is  dropped  by  the  feed  belt  as  it 
passes  over  the  roller,  while  the  magnetic  is  lifted  by  the  magnets  to  the 
take-off  belt  and  is  carried  forward  thereby.  In  operation  the  take-off  belt 
is  needed  more  to  keep  the  pole  points  clear  than  to  hold  and  carry  the  ore. 

Theory  of  the  Wetherill  System. — It  will  be  observed  that  the  Wetherill 
machines  do  not.  differ  essentially  in  mechanism  from  certain  of  the  simple 
magnetic  separators  which  have  been  used  for  various  purposes.  Their 


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PS 

I 

TJ1 


525 

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OF  THE 

UNIVERSITY 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES.  275 

novelty  and  the  principle  upon  which  they  are  designed  are  in  the  produc- 
tion of  an  intense  magnetic  field,  which  is  obtained  by  the  almost  perfect 
condensation  in  the  pole  points  of  the  vast  number  of  magnetic  lines  gen- 
erated in  the  large  and  correctly  proportioned  cores,  yokes  and  pole  pieces. 
Professor  William  A.  Anthony  expressed  concisely  the  difference  between 
the  principles  of  the  Wetherill  and  other  magnetic  separators  as  follows:1 
"Instead  of  small  magnet  cores  and  large  air  gap  area,  there  should  be  large 
magnet  cores  and  small  air  gap  area — large  magnet  cores  to  reduce  the 
resistance  and  permit  of  the  production  of  a  large  number  of  magnetic  lines, 
and  a  small  air  gap  area  through  which  all  those  lines  must  pass,  and  in 


FIG.  44. — MODERN  FORM  OF  WETHERILL  SEPARATOR,  THREE  POLE  TYPE. 

which,  therefore,  they  are  crowded  together,  which  is  the  same  thing  as 
saying  that  the  magnetic  force  is  intensified."  This  condensation  is  so  com- 
plete in  the  Wetherill  machines  that  the  current  of  one  bluestone  cell,  such 
as  is  used  in  telegraphy,  is  too  powerful  to  permit  a  satisfactory  separation 
of  magnetite,2  and  for  that  purpose  its  strength  must  be  reduced  by  resist- 
ance coils,  in  order  to  prevent  tangling  and  allow  the  belts  to  draw  the  ore 
away  from  the  pole  points.  The  magnetic  intensity  of  the  poles  can  be 
regulated  with  such  delicacy,  by  varying  the  current,  that  from  a  mixture 
of  garnet,  monazite  and  rutile  the  monazite  can  be  removed  at  one  operation, 
after  which  by  a  slight  variation  in  the  current  the  garnet  and  rutile  can 
bo  separated. 

i  Cassier's  Magazine,  March,  1898,  p.  433. 

-  IT.  A.  T.  Wilkens  and  H.  B.  C.  Nitze,  Trans.  Am.  Inst.  Min.  Eng.,  XXVI,  361. 


276  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

The  volume  of  current  required  by  the  Wetherill  magnets  is  compara- 
tively small.  In  the  separation  of  the  franklinite  from  the  Xew  Jersey  zinc 
ore,  three  to  eight  amperes  and  16  to  30  volts  are  necessary;  for  limonite 
and  pyrolusite  10  to  15  amperes  are  required.  The  capacity  of  the  machines 
is  from  600  to  12,000  Ib.  per  hour,  depending  upon  the  number  of  pole 
pieces,  the  width  of  the  carrying  belt,  the  speed  of  the  belt,  the  volume  and 
intensity  of  the  current,  and  the  size  and  character  of  the  material  operated 
upon. 

Conditions  of  Practical  Application. — In  the  employment  of  the  Wetherill 
process  for  the  separation  of  minerals  it  is  important  to  subject  the  ore  to  a 
pulverization  sufficiently  fine  to  free  the  component  minerals,  which  must 
then  be  sized  carefully  by  screening.  It  is  quite  as  important  to  avoid  the 
production  of  an  excessive  proportion  of  fines  in  crushing  ore  for  this  process 
as  it  is  in  crushing  for  gravity  separation.  It  it  impossible  to  determine  in 
advance  the  proper  belt-speed  and  magnetic  intensity  of  the  separators,  which 
can  be  settled  only  by  experiment.  The  more  intense  the  concentration  of 
the  lines  of  force  in  the  magnets,  and  the  greater  the  quantity  of  electric 
energy,  the  more  speed  at  which  the  belt  may  be  run,  and  the  greater  the 
speed  of  the  belt  the  greater  is  the  capacity  of  the  separator.  In  practice, 
however,  a  limit  to  the  capacity  is  soon  reached,  inasmuch  as  the  intensity 
of  the  magnetic  field  cannot  be  greatly  increased,  since  the  poles  of  the 
electromagnets  are  designed  to  correspond  approximately  to  a  determined 
maximum  of  lines  of  force  produced  in  the  magnetic  field.  The  quantity 
of  current  required  for  a  separation  cannot  be  predicted  in  advance,  more- 
over, because  of  the  variability  in  the  magnetic  permeability  of  the  same 
mineral  from  different  deposits. 

PRACTICAL  EESULTS  OF  THE  WETHERILL  SYSTEM. — The  Wetherill  system 
is  now  in  use  for  the  treatment  of  zinc  ores  at  Franklin  Furnace,  N.  J., 
Austin ville,  Va.,  Warren,  N.  H.,  Washington,  Ariz.,  Kokomo,  Denver 
and  Canon  City,  Colo.,  at  Ems,  Gladbach,  Hamborn,  Lohmansfeld  and 
Friedrichssegen,  in  Germany,  and  at  Melbourne  and  Broken  Hill,  N.  S.  W. 
It  has  been  tried  on  a  working  scale  at  Joplin,  Mo.,  but  the  plant  there  is 
not  at  present  in  operation.  The  results  obtained  at  some  of  those  places 
are  summarized  briefly  in  the  following  paragraphs : 

Austinville,  Va. — In  separating  a  mixture  of  calamine  and  limonite  ob- 
tained from  the  jigs  at  the  works  of  the  Wythe  Lead  and  Zinc  Co.  at  Aus- 
tinville, Va.,  100  parts  of  ore.  assaying  18-00%  Fe  and  29-57%  Zn,  yielded 
67  parts  of  zinc  product,  assaying  341%  Fe  and  4140%  Zn.  and  33  parts 
of  iron,  assaying  4945%  Fe  and  5-58^  Zn. 


MECHANICAL    CONCENTRATION    OF    ZINC    O1IES.  £t( 

Mine  Hill  and  Franklin  Furnace,  N.  J. — The  largest  and  most  important 
installation  of  the  Wetherill  process  has  been  made  by  the  New  Jersey  Zinc 
Co.  at  Mine  Hill,  where  a  plant  of  500  tons  per  day  capacity  has  been  in 
operation  since  1896,  while  a  new  mill  of  1,000  tons  per  day  capacity  at 
Franklin  Furnace  was  completed  in  1901.  Both  of  these  are  for  the  sepa- 
ration of  the  mixed  franklinite  and  willemite  obtained  from  the  mines  near 
by,  which  have  been  described  in  a  previous  chapter. 

At  the  Mine  Hill  works  the  ore  passes  first  over  a  grizzly  with  1-5  in. 
spaces,  the  undersize  going  to  an  inclined  screen  with  0-5  in.  holes  and  the 
oversize  to  a  Blake  crusher,  which  delivers  its  product  to  a  screen  with  1  in. 
holes.  The  undersize  from  the  latter  screen  is  received  on  a  picking  belt, 
which  also  takes  the  oversize,  this  arrangement  being  to  reduce  the  wear  of 
the  belt,  inasmuch  as  the  coarse  ore  falls  upon  a  cushion  of  fine  ore.  The 
oversize  from  the  0-5  in.  screen  is  delivered  to  the  same  belt.  Clean  waste 
is  picked  from  the  belt,  which  conveys  the  enriched  ore  to  a  Blake  duplex 
crusher.  The  product  of  the  latter  passes  to  two  trommels  with  0-25  in. 
holes,  from  which  the  oversize  goes  to  the  rolls  and  the  undersize,  together 
with  the  material  which  passed  through  the  0-5  in.  screen,  is  delivered  to 
an  Edison  dryer.  The  latter  is  a  tower,  3  ft.  square  and  24  ft.  high,  with 
zigzag  shelves,  set  at  45°,  down  which  the  ore  slides  while  the  products  of 
combustion  from  a  fireplace  pass  over  it. 

The  dry  ore  is  delivered  to  four  trommels,  covered  with  eight-mesh  wire 
cloth,  from  which  the  oversize  is  crushed  finer  by  rolls  and  then  goes  with 
the  undersize  to  six  trommels,  covered  with  10-mesh  wire  cloth.  The  over- 
size from  the  10-mesh  screens  is  passed  through  a  four-mesh  screen  to  remove 
nails,  splinters  of  wood  and  other  rubbish,  and  after  being  crushed  finer  by 
rolls  is  returned  to  the  10-mesh  trommels.  The  material  which  passes 
through  the  10-mesh  screens  is  received  in  storage  bins,  whence  it  is  drawn 
to  the  magnetic  separators  as  required. 

In  the  separating  department  the  ore  passes  first  over  six  Wetherill  double 
machines,  which  yield  franklinite  concentrate  and  mixed  tailings.  The  lat- 
ter go  to  two  trains  of  sizing  trommels,  one  on  each  side  of  the  mill.  Each 
train  consists  of  four  trommels  covered  respectively  with  wire  cloth  of  16, 
24,  30  and  50-mcsh.  They  make  five  sizes  of  ore,  which  are  delivered  to 
storage  bins,  whence  they  are  drawn  to  separators  on  each  side  of  the  mill. 
Each  size  passes  over  a  series  of  three  machines,  the  second  taking  the  tail- 
ings of  the  first  and  the  third  those  of  the  second,  the  concentrate  of  each 
machine  being  franklinite.  The  machines  which  treat  the  finest  size  are  of 
the  sloping  type ;  the  others  are  horizontal. 

On  e'ach  side  of  the  mill  there  are  four  Harz  jigs,  of  which  "N"o«.  1.  2  and 


-78  PRODUCTION    AND    PROPERTIES    OF    ZINC. 

1  have  four  compartments,  and  No.  3  has  three  compartments.  These  re- 
ceive the  tailings  from  the  first  four  series  of  magnetic  machines  and  make 
a  concentrate,  consisting  of  willemite  and  zinkite,  and  tailings  consisting 
chiefly  of  calcite  and  quartz.  The  concentrate  is  dried  in  a  revolving  cylinder 
with  longitudinal  ribs  inside,  which  is  heated  by  direct  firing.  The  tailings 
from  the  fifth  magnetic  machines  are  so  rich  in  willemite  and  zinkite  that 
they  do  not  require  a  further  concentration  by  gravity. 

According  to  J.  P.  Wetherill,1  the  cost  of  treating  4,812  long  tons  of  ore 
in  February,  1897,  was  74-54c.  per  ton,  of  which  53-32c.  was  for  labor,  8-77c. 
for  coal  and  12-45c.  for  repairs,  renewals  and  miscellaneous  supplies.  Out 
of  30,311  tons  separated  up  to  April  1,  1897,  there  were  produced  20,455 
tons  of  franklinite,  or  67-48%,  7,271  tons  of  willemite  and  zinkite,  or 
23-99%,  and  2,585  tons  of  tailings.  The  franklinite  assayed  29-47%  Fe, 
13-57%  Mn,  and  22-94%  Zn.  The  mixed  willemite  and  zinkite  assayed 
2-20%  Fe,  5-15%  Mn,  and  48-96%  Zn.  The  grade  of  the  latter  varied  from 
46-5%  to  53%  Zn,  according  to  the  quantity  of  zinkite  contained  in  the  ore. 
The  tailings  averaged  4-19%  Zn.2  In  1900  the  two  mills  treated  160,640 
long  tons  of  ore,  which  yielded  148,917  tons  of  concentrates,  or  nearly  93%. 

In  mill  No.  2,  near  Franklin  Furnace,  the  Edison  system  of  fine  crushing 
was  first  employed,  but  it  was  found  to  produce  too  high  a  proportion  of 
fines  and  ordinary  rolls  were  substituted  for  the  Edison  kind.  This  mill  has 
17  machines,  each  with  three  pairs  of  magnets,  and  treats  70  tons  of  ore  per 
hour  at  a  cost  of  about  40c.  per  ton. 

Joplin,  Mo. — At  the  Empire  Zinc  Co.'s  smeltery  at  Joplin,  Mo.,  Wetherill 
machines  were  employed  for  the  removal  of  iron  from  certain  concentrated 
blende  which  was  considerably  higher  in  pyrites  than  the  average  of  the 
Joplin  district.  The  ore  was  first  roasted  dead,  as  in  the  ordinary  pre- 
liminary to  distillation,  the  iron  sulphide  being  thereby  converted  to  oxide, 
which  is  susceptible  to  the  magnetic  influence  of  the  Wetherill  machines. 
The  roasted  ore  delivered  to  the  machines  assayed  8%  Fe.  It  was  passed 
over  two  machines  in  series  at  the  rate  of  10  tons  per  24  hours,  the  result 
being  a  zinc  product  assaying  only  2%  Fe,  which  went  to  the  distillation 
furnaces,  and  an  iron  product  assaying  15%  Zn,  which  was  thrown  away. 

Denver,  Colo. — At  the  works  of  the  Colorado  Zinc  Co.  mixed  sulphide  ore 
from  Leadville  and  Kokomo  is  treated.  The  ore  is  crushed  to  30-mesh 
size  by  means  of  a  Gates  crusher  and  rolls,  and  after  an  hydraulic  classifica- 
tion is  washed  on  eight  Wilfley  tables.  The  latter  produce  from  Leadville 
ore  a  galena  concentrate  assaying  about  50%  Pb,  13%  Fe,  9%  Zn  and 

1  Eng.  &  Min.  Journ.  July  17  and  24, 1897.       of  27-5%  Zn  in  the  crude  ore  in  the  act 

2  These  analyses   show   an   average   tenor        milling  of  30,311  tons. 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES.  279 

10  oz.  Ag.  per  ton,  and  a  pyrites-blende  assaying  about  21-5%  Fc,  30% 
Zn  and  6%  Pb.  The  pyrites-blende  is  dried  and  then  is  fed  to  the  Wetherill 
magnetic  separators,  of  which  there  are  two;  they  make  a  blende  concen- 
trate assaying  about  50%  Zn,  12%  Fe  and  1%  Pb  (the  iron  being  chiefly 
contained  in  the  blende  as  monosulphide),  and  pyrites  tailings  which  con- 
tain about  7  or  S%  Zn  and  10%  Pb.  The  tailings  from  the  separator  are 
mixed  with  the  galena  concentrate  from  the  Wilfley  tables  and  sold  to  the 
lead  smelters.  The  Wetherill  separators  treat  about  24,000  Ib.  of  material 
per  24  hours  apiece.  They  are  of  the  design  shown  in  Fig.  43.  The  belt 
is  18  in.  wide  and  there  are  three  magnets,  which  require  respectively  7,  11' 
and  22  amperes  of  current,  a  total  of  40  amperes,  at  115  volts. 

Lohmannsfeld,  Germany. — An  interesting  installation  of  the  Wetherill 
process  has  been  made  at  Lohmannsfeld,  in  the  Siegen  district,  Germany,  at 
which  place  a  deposit  of  ore  consisting  of  galena,  siderite  and  blende,  with 
a  gangue  of  quartz  and  quartzite  is  Avorked.  The  siderite  (spathic  iron  ore) 
contains  up  to  12%  of  manganese.  By  the  ordinary  process  of  mechanical 
separation  it  was  impossible  to  obtain  from  this  ore  any  concentrate  but 
galena  of  various  classes,  while  blende  and  spathic  iron  could  be  got  only  b}' 
an  expensive  system  of  hand  sorting.  The  third  and  fourth  compartments 
of  the  Harz  jigs  furnished  always  a  mixed  product  containing  from  2  to  3% 
of  gangue  and  15  to  22%  of  blende,  according  to  the  tenor  of  blende  in  the 
crude  ore,  the  remainder  being  spathic  iron.  The  quantity  of  this  mixed 
product  ranged  from  600  to  750  metric  tons  per  month.  In  order  to  pro- 
duce a  marketable  blende  it  was  necessary  to  roast  the  mixture  to  transform 
the  ferrous  carbonate  into  magnetic  oxide,  which  could  then  be  removed  by 
ordinary  magnetic  separators.  The  company  operating  at  Lohmannsfeld 
not  being  able  to  install  roasting  furnaces  at  its  mines,  was  obliged  to  sell  its 
mixed  product  under  very  unfavorable  terms,  the  average  price  realized  at  the 
mine  being  from  12  to  15  marks  per  metric  ton.  Experiments  in  separating 
the  ore  crushed  to  3  mm.  size  by  means  of  the  Wetherill  machines  gave  such 
favorable  results  that  it  was  determined  to  make  an  installation  of  them. 

The  crude  mineral  sent  to  the  Wetherill  plant  is  the  middlings  from  the 
Harz  jigs  of  the  wet-dressing  works,  varying  in  size  from  1  to  10  mm.,  and 
containing  from  5  to  20%  of  water.  The  arrangement  of  the  plant  is  shown 
in  the  accompanying  engravings,  Figs.  45  to  48.  The  mineral  is  dried 
while  being  moved  forward  by  means  of  a  screw  conveyor,  the  trough  of 
which  is  made  double,  of  cast  iron,  exhaust  steam  from  the  engine  being 
passed  between  tihe  two  sections.  The  speed  of  the  screw  A  is  such  that  the 
mineral  remains  in  the  trough  30  minutes,  while  in  the  trough  B  it  remains 
25  minutes.  These  conveyors  discharge  the  dried  mineral  into  the  primary 


280 


PRODUCTION    AND   PROPERTIES    OF    ZINC. 


MECHANIC  A  L    (ONCKX TRATION    OF    ZINC    OKKS. 


281 


trommels,  A^  and  A2,  by  which  it  is  separated  into  two  classes.  That 
which  is  finer  than  3  mm.  falls  into  the  boot  of  the  elevator  Clf  which  raises 
it  to  the  main  system  of  classifying  trommels;  that  which  is  larger  than 
3  mm.  passes  to  two  sets  of  rolls,  whereby  it  is  crushed,  falling  thence  into 
the  pit  B2f  whence  the  elevator  C2  raises  it  to  the  trommel  A2,  to  separate  it 
into  mineral  smaller  than  3  mm.,  which  falls  into  the  pit  B^  and  mineral 
larger  than  3  mm.,  which  is  returned  to  the  rolls. 


j- 


4- 


FIG  46.  —  TRANSVERSE  SECTION  OF  WETHERILL  MAGNETIC  SEPARATING 
PLANT  AT  LOHMANNSFELD,  GERMANY. 

Scale,  1  :200. 

All  the  mineral  crushed  to  pass  a  3-mm.  screen  is  collected  therefore  in 
the  pit  Blf  whence  the  elevator  Cl  raises  it  to  the  train  of  sizing  trommels,  to 
reach  which,  however,  it  has  to  be  conveyed  by  a  horizontal  belt  Z>,  over 
which  it  set  a  powerful  electro-magnet  to  pick  out  strongly  magnetic  articles 
such  as  rivet  heads,  small  pieces  of  iron  and  steel,  etc. 

The  sizing  trommels  separate  the  mineral  into  four  classes,  namely,  3  to  2 
mm.,  2  to  14  mm.,  14  to  0-75  mm.,  and  that  which  is  smaller  than  0-75  mm. 
The  separated  classes  pass  thence  over  three  series  of  Wetherill  separators  of 
the  two-pole  and  three-pole  t}^pes,  arranged  two  in  a  series.  In  the  first 
member  of  each  series,  pure  spathic  iron  is  separated  by  a  feeble  current. 
The  diamagnetic  product  passes  to  the  lower  machine  where  the  intensity 


282 


PKODL'CTIOX    AND   PROPERTIES    OF    ZINC. 


oost * oose -*- ooos 


MECHANICAL    CONCENTRATION    OF   ZINC    ORES. 


283 


of  the  magnetic  field  is  greater,  enabling  a  mixed  product  of  blende  and 
spathic  iron  to  be  separated  as  the  paramagnetic,  while  pure  blende  remains 
as  the  diamagnetic.  The  blende  of  Lohmannsfeld  is  diamagnetic  even  in 
magnetic  fields  of  the  greatest  intensity,  because  of  the  absence  of  iron  and 
manganese  in  its  composition.  The  width  of  the  points  of  the  poles  of  the 


FIG.  48. — TRANSVERSE  SECTION  OF  WETHERILL  MAGNETIC  SEPARATING 
PLANT  AT  LOHMANNSFELD,  GERMANY. 

4 

Wetherill  machines  used  at  Lohmannsfeld  is  340  mm.  The  belt  speed  of 
the  upper  machine  is  40  m.  per  minute;  of  the  lower  25  m.  The  current 
employed  is  of  65  volts  electromotive  force;  the  upper  machine  of  the  two- 
pole  type  works  with  12  amperes ;  the  lower  with  14  to  16  amperes.  For 
machines  of  the  three-pole  type  the  corresponding  figures  are  five  amperes 
for  the  upper  and  eight  amperes  for  the  lower. 

The  plant  is  capable  of  separating  3  to  3-5  metric  tons  of  crude  mineral 
per  hour,  the  crew  required  for  its  operation  being  as  follows :  One  fore- 
man, five  16  to  18-year-old  boys,  one  machinist  (engineman)  and  one  stoker. 
The  cost  of  treatment  (year's  average)  is  14  marks  per  metric  ton  of  crude 


284  PRODUCTION   AND   PROPERTIES   OF   ZINC. 

mineral,  no  amortization  of  the  plant  being  reckoned.  The  plant  cost  about 
100,000  marks.  Allowing  20%  for  amortization,  =20,000  marks  per  an- 
num on  8,000  tons  (the  capacity  of  the  plant)  the  total  cost  of  treatment 
is  3-9  marks  per  ton.  The  value  of  the  ore  sent  to  the  works  being  12  to  15 
marks,  the  total  cost  of  production  is  15-9  to  18«9  marks.  The  value  of  the 
blende  recovered  from  a  ton  of  crude  mineral  varies  from  32  to  35  marks, 
so  that  the  plant  yields  16X8,000  marks=128,000  marks  per  annum,  not 
allowing  for  royalty  on  the  process. 

Broken  Hill,  N.  8.  W. — The  middlings  of  the  dressing  works  of  Broken 
Hill,  containing  a  mixture  of  galena,  blende  and  garnet,  were  successfully 
treated  in  1899  (when  the  price  of  zinc  was  high  and  exporting  conditions 
were  favorable)  by  the  Wetherill  process,  for  the  application  of  which  there 
were  installed  two  plants,  one  with  a  capacity  of  30,000  to  35,000  metric 
tons  per  annum,  the  other  with  a  capacity  of  20,000  tons.  The  material  oper- 
ated upon  assayed  25  to  30%  Zn,  8  to  10%  Pb  and  300  to  400  g.  of  silver 
per  metric  ton.1  In  separating  the  component  minerals  by  the  Wetherill 
process  the  ore  was  first  dried  and  then  classified  into  three  or  four  sizes. 
The  ore  being  already  of  less  than  2-8  mm.  size  for  the  most  part,  it  was 
necessary  to  crush  only  the  small  percentage  which  was  in  excess  of  that 
size.  The  dry,  sized  mineral  was  delivered  to  the  Wetherill  separators,  ar- 
ranged in  series.  The  first  machine  of  each  series  separated  the  garnet  and 
rhodonite,  amounting  to  15  to  25%  of  the  weight  of  the  crude  mineral.  The 
losses  in  blende  and  argentiferous  galena  in  effecting  the  first  separation 
were  very  small.  The  tailings  from  the  first  machines  passed  to  others, 
which  had  a  more  powerful  magnetic  field  and  separated  as  the  magnetic 
product  blende  assaying  from  41  to  45%  Zn  and  representing  50  to  75%  oi 
the  weight  of  the  crude  mineral;  this  blende  contained  still  about  8  to  10% 
Pb  and  350  to  400  g.  of  silver  per  ton.  As  diamagnetic  product  there  was 
obtained  a  mixture  of  quartz  with  10  to  20%  Pb,  10  to  20%  Zn  and  300  to 
500  g.  of  silver  per  toh,  this  product  constituting  about  20%  of  the  weight 
of  the  original  mineral;  it  was  subjected  to  a  further  process  of  gravity 
separation  in  the  ordinary  manner,  yielding  a  concentrated  product  of  argen- 
tiferous galena.  The  total  recovery  of  zinc  varied  from  80  to  90%  of  that 
which  was  contained  in  the  crude  middlings.  The  cost  of  the  process  was 
said  to  be  a  little  less  than  the  cost  of  wet  concentration  in  the  ordinary 
manner  as  practised  at  Broken  Hill. 

The  figures  quoted  above  were  taken  from  a  paper  by  M.  Smits,  read  b( 

1ThIs   material    was    considerably    richer  Mineral  Industry,  IX,  752)  contain  5  to 

than  the  average  of  the  "zinc  middlings"  Pb,   15  to  25%  Zn,  and  5  to  10  oz. 

made  by  the   Broken   Hill    dressing   works,  per  ton.     Data  as  to  the  assay  of  the  en 

which  according  to  T.  J.  Greenway   (in  The  ore  will  be  found  on  p.  229. 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES.  285 

fore  the  Congres  International  des  Mines  et  de  la  Metallurgie  of  the  Expo- 
sition of  1900  at  Paris  and  reprinted  in  the  Bulletin  de  la  Societe  de  I'ln- 
dustrie  Minerale,  vol.  XIV,  1900.  According  to  T.  J.  Greenway,  a  recognized 
authority  on  the  dressing  of  the  Broken  Hill  ore,  the  separation  of  the  ore 
in  the  Wetherill  plants  was  made  in  three  classes,  namely :  I,  non-magnetic 
material  consisting  chiefly  of  quartz,  blende  containing  a  large  portion  of 
lead,  and  free  galena,  the  whole  averaging  18  to  20%  Pb,  18  to  22%  Zn, 
and  8  to  12  oz.  silver  per  ton.  II,  weakly  magnetic  concentrates  containing 
8  to  10%  Pb,  35  to  42%  Zn,  and  8  to  12  oz.  silver  per  ton;  and  II,  strongly 
magnetic  material  consisting  chiefly  of  rhodonite  and  garnet  and  assaying 
4  to  6%  Pb,  6  to  8%  Zn,  and  4  to  6  oz.  silver  per  ton. 

The  zinc  product  was  shipped  to  European  smelters ;  the  other  products 
were  piled  up  for  future  treatment.  The  Wetherill  plants  at  Broken  Hill 
are  now  (1901)  closed  down,  blende  concentrates  of  the  grade  made  not 
affording  any  profit  over  and  above  the  cost  of  production  under  the  exist- 
ing market  conditions. 

It  is  obvious  that  the  Wetherill  process  at  Broken  Hill  was  only  partially 
successful,  the  unsatisfactory  results  being  ascribable  to  the  exceedingly  diffi- 
cult character  of  the  ore.  "The  above  mentioned  operations,  as  well  as  ex- 
haustive experiments  carried  on  by  some  of  the  mining  companies,  have 
rendered  it  evident  that  the  average  blende  concentrate  obtainable  from  the 
Broken  Hill  sulphide  ore  is  unavoidably  a  complex  product  containing  from 
30  to  40%  Zn,  from  6  to  12%  Pb,  and  from  6  to  12  oz.  silver  per  ton" 
(Green way,  loc.  cit.). 

LA  TRIEUSE  SEPARATOR. — This  machine  was  used  in  1892  at  Laurium, 
Greece,  for  the  removal  of  iron  from  a  roasted  pyrites  and  blende.  It  is 
described  as  having  had  two  powerful  electro-magnets,  with  poles  terminat- 
ing in  finger-like  ends,  mounted  in  a  frame  and  swung  by  a  rod,  with  a  uni- 
versal joint,  from  the  end  of  a  counterpoised  lever  over  a  tray  of  ore.  The 
current  could  be  adjusted  to  suit  the  degree  of  roasting  to  which  the  ore 
had  been  subjected.  The  iron  oxide  having  been  picked  up  by  the  magnet, 
the  latter  was  swung  to  one  side  over  a  receptacle  into  which  the  mineral 
was  dropped  by  shutting  off  the  current.  To  work  300  to  1,000  kg.  of  ore, 
assaying  22%  Zn,  in  10  hours,  required  2-5  to  3  amperes  and  40  volts.1 

CLEVELAND-KNOWLES  SEPARATOR. — This  is  a  new  magnetic  separator  of 
the  high  intensity  type,  in  which  it  is  aimed  to  prevent  magnetic  leakage 
except  across  the  air  gap,  with  the  consequent  increase  of  magnetic  intensity 
at  that  point,  which  should  be  directly  proportional  to  the  decrease  of  leak- 

1  Hugues  Daviot,  Comptes  Rendus  Mensuels  del'Industrie  Mineral*,  Sainte  Etienne, 
May.   1S03;  The  Mineral  Industry,  II,  827. 


286 


PRODUCTION  AXD  PROPERTIES  OF  ZINC. 


age  at  other  points.  According  to  Mr.  W.  P.  Cleveland,  one  of  the  inventors 
of  the  machine,  to  whose  courtesy  these  notes  are  due,  that  result  is  attained 
by  providing  a  return  path  for  the  lines  of  force,  from  pole  to  pole  of  the 


5 


o 

I 

CJ 


magnet,  of  a  greater  permeability  than  air,  wherefore  all  lines  of  force  will 
pass  through  the  conductor  in  preference  to  leaking  through  the  air  against 
a  greater  resistance,  and  will  pass  across  the  magnetic  field  with  all  or  nearly 
all  of  the  initial  intensity. 


MECHANICAL   CONCENTRATION    OF   ZINC    ORES. 


287 


In  construction,  the  magnet  is  iron-clad,  i.e.,  the  coil  is  entirely  sur- 
rounded by  one  of  the  poles  itself.  The  magnetic  field  is  therefore  endless, 
being  in  the  form  of  a  circle,  one  pole  concentric  with  the  other  and  the  space 
between  them  filled  with  a  diamagnetic  material.  Two  of  these  magnets, 
termed  respectively  the  "rougher"  and  the  "cleaner"  are  revolved  in  a  hori- 


I  I 

FIG.  50. — CLEVELAND-KNOWLES  MAGNETIC  SEPARATOR, 

END   ELEVATION. 

Scale,  V2  in.=l  ft. 

zontal  plane  above  an  endless  conveying  belt,  upon  which  the  ore  to  be  sepa- 
rated is  evenly  spread.  In  passing  beneath  the  magnets,  each  of  which  is 
placed  so  as  to  offset  the  belt  on  one  side,  the  magnetic  mineral  is  attracted 
and  carried  to  one  side  of  the  belt,  where  it  is  removed  from  the  magnet  by 
a  scraper  and  is  dropped  into  a  collecting  chute.  A  current  of  0-5  ampere 


288 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 


is  employed  for  the  "rougher"  magnet  and  one  of  6*5  amperes  for  the 
"cleaner/7 

The  Cleveland-Knowles  separator  has  been  in  use  since  September,  1900, 
at  the  works  of  the  Joplin  Separating  Co.,  at  Joplin,  Mo.,  where  about  40 


Block 


FIGS.  51  AND  52. — CLEVELAND-KNOWLES  MAGNETIC  SEPARATOR. 

LOCATION   OP   COILS  IN   MAGNETS. 

Scale,  1  in.=l  ft. 

tons  per  £4  hours  of  blende-pyrites  concentrates  are  treated.     The  mixture 
is  first  subjected  to  a  light1  preliminary  roasting,  in  order  to  render  th( 

1  Doctor  William  B.  Phillips  as  the  result  more  than  one  third  of  the  sulphur  of  th< 

of  a  series  of  experiments  for  the  separation  ore  in  the  roasting  process  preliminary 

of  pyrlte  from  blende  produced  by  a  mine  In  magnetic  separation ;  and  that  there  was 

Sevler  County,  Arkansas,  came  to  the  con-  fact    a    positive    disadvantage    in    strongl] 

elusion  that  it  was  unnecessary  to  remove  roasting  the  ore,   which  led  not  only  to 


MECHANICAL    CONCENTRATION    OF    ZINC    ORES. 


289 


pyrite  magnetic,  and  is  then  passed  to  the  separators.     The  results  of  some 
work  that  has  been  done  are  shown  in  the  following  table : 


.Wood 

Block : 


FIGS.  53  AND  54. — CLEVELAND-KNOWLES  MAGNETIC  SEPABATOB. 


LOCATION  OP  COILS  IN  MAGNETS. 
Scale,  1  in.=l  ft. 


Source  of  Ore. 

Quantity 
Treated. 

Assay  of  Crude. 
%  Zn.       %  Fe. 

Assay  of  Concentrate. 
%  Zn.           %  Fe. 

Galena  Kan  

10'5  tons 
43'0      " 
27-0      " 
7-0      " 
22-0      " 

53  97 
47-19 
45-25 
51-56 
44'60 

5-00 
9-84 
9-67 
6.13 
12  39 

63  25 
59-45 
58-35 
57-20 
62-15 

1-33 
1-00 
1-29 
2-40 
1-02 

Joplin,  Mo  

Oronogo,  Mo  

The  Cleveland-Knowles  separator  is  controlled  by  the  Magnetic  Separat- 
ing Co.,  of  Joplin,  Mo.     It  is  illustrated  in  Figs.  46  to  51. 


diminished  yield  of  zinc  concentrate  but 
also  to  a  lower  tenor  of  zinc  in  it  (Eng. 
&  Min.  Journ.,  Nov.  30,  1901,  p.  711).  The 


kind  of  separator,  with  which  these  experi- 
ments were  made,  was  not  stated  by  Doctdr 
Phillips. 


XII. 
SAMPLING  AND  VALUATION  OF  ORES. 

The  value  of  a  zinc  ore  depends  upon  its  tenor  in  zinc  and  objectionable 
impurities,  especially  iron  and  manganese,  and  its  character,  oxidized  or 
sulphide;  it  is  influenced  also  by  its  contents  in  lead  and  silver,  always 
in  so  far  as  they  reduce  the  percentage  of  zinc  and  contaminate  the  spelter 
and  in  certain  cases  in  so  far  as  they  may  be  recovered  separately.  Obviously 
the  value  of  a  zinc  ore  is  affected  also  by  the  market  price  of  the  m<etal. 
The  most  valuable  zinc  ore  imaginable  is  a  pure,  dense  zinc  oxide,  containing 
80-344%  Zn,  which  is  the  compound  reducible  at  the  minimum  cost,  and 
with  the  minimum  loss  of  metal.  As  the  tenor  in  zinc  falls  the  cost 
of  smelting  rises;  consequently  the  same  quantity  of  zinc  in  an  ore 
assaying  70%  is  worth  more  than  in  an  ore  assaying  only  50%. 
For  example,  suppose  there  be  two  ores  of  similar  character, 
except  that  one  contains  70%  Zn,  while  the  other  has  only  50% 
the  cost  of  freights,  smelting,  etc.,  being  $10  per  2,000  Ib.  of  ore  and  the 
recovery  of  metal  80%.  The  high  grade  ore  on  the  above  assumption  will 
yield  1,120  Ib.  of  zinc  per  ton  and  the  low  grade  800  Ib.  Assuming  that  the 
product  is  worth  5c.  per  Ib.,  delivered  at  the  smelting  works,  the  value  (with- 
out reckoning  amortization,  profit,  etc.)  of  the  high  grade  ore  would  be 
$56- — $10=$46  and  the  value  to  the  miner  of  the  zinc  in  it  would  be 
$46-f-l,400=3-286c.  per  Ib. ;  similarly,  the  value  of  the  low  grade  ore  would 
be  $40— $10=$30  and  $30-f-l,000=3-0c.  per  Ib.  of  zinc.  Obviously,  the 
decrease  in  the  value  of  the  zinc  in  an  ore  with  decrease  in  the  grade  of 
the  latter  is  greater  the  higher  the  cost  of  carriage  to  the  smelter's  works 
and  the  cost  of  smelting  per  ton  of  ore.  In  the  above  example  the  cost  of 
smelting  per  ton  of  ore  and  recovery  of  metal  have  been  assumed  the  same 
for  the  high  grade  as  for  the  low  grade,  though  practically  there  would  be  a 
difference  in  favor  of  the  higher  grade. 

The  cost  of  smelting  a  calcined  or  roasted  ore  is  increased  moreover  by 
the  presence  of  those  impurities  (sulphur,  iron  and  manganese),  which  may 

290 


SAMPLING   AND   VALUATION    OF    ORES.  291 

cause  an  increased  loss  of  zinc  and  perhaps  a  greater  consumption  of  fuel  and 
reduction  material.  In  referring  the  cost  of  smelting  to  terms  of  crude  ore 
much  will  depend  upon  the  relative  cost  of  calcining  calamine  and  roasting 
blende,  the  percentage  of  weight  lost  in  each  process,  and  the  value  that 
may  be  realized  from  the  sulphur  of  the  blende  in  the  manufacture  of  sul- 
phuric acid.  The  effect  of  other  impurities  such  as  lime,  fluorspar,  arsenic 
and  antimony,  which  may  contaminate  the  products  and  otherwise  interfere 
in  the  process,  must  also  be  considered.  It  is  essential  therefore  in  estab- 
lishing the  value  of  a  zinc  ore  to  determine  its  composition ;  as  a  preliminary 
to  which  a  representative  sample  is  necessary. 

In  Europe  most  of  the  zinc  ore  which  is  smelted  is  bought  on  the  basis 
of  its  zinc  tenor  as  shown  by  sampling.  In  the  United  States  comparatively 
little  is  bought  in  that  manner.  This  is  because  of  the  peculiar  conditions 
of  the  Joplin  district,  where  the  production  of  ore  is  made  by  a  host  of  small 
miners,  who  expect  cash  immediately  upon  the  delivery  of  their  product, 
or  rather  at  the  end  of  the  week  of  delivery  and  in  many  cases  desire  to 
realize  on  less  than  carload  lots.  It  would  be  extremely  difficult  in  view  of 
the  conditions  of  production  to  change  the  custom  of  buying  and  selling 
the  ore  so  as  to  put  it  upon  a  strict  basis  of  sample  and  assay,  although 
during  the  last  two  or  three  years  there  has  been  a  tendency  to  do  so  as  far 
as  practicable. 

Besides  serving  as  a  basis  for  the  purchase  of  ore  a  sample  is  important 
as  a  basis  for  the  control  of  the  smelting  process,  wherefore  even  if  the  ore 
be  not  bought  in  that  manner  everything  received  at  the  smeltery  should  be 
sampled  there  for  a  guide  in  the  metallurgical  work.  It  is  only  recently  that 
this  has  been  done  at  all  in  the  Kansas  and  Missouri  smelting  district,  but 
most  of  the  large  concerns  now  employ  chemists  and  sample  the  ore  received 
more  or  less  carefully.  Systematic  sampling  may  also  be  made  of  ad- 
vantage in  the  operation  of  dressing  works,  although  it  is  only  in  rare 
instances  that  the  design  provides  for  doing  so,  and  the  introduction  of  a 
cheap  and  efficient  system  presents  considerable  difficulty.  The  only  way 
whereby  the  efficiency  of  a  milling  or  metallurgical  process  can  be  accu- 
rately determined  is  a  comparison  between  the  valuable  contents  of  the 
crude^  material  treated  and  those  of  the  products  obtained.  Deductions 
from  any  other  data  are  likely  to  be  misleading.  If  losses  were  always 
determined  accurately,  many  results  which  are  considered  satisfactory 
would  prove  not  so,  unsuspected  leaks  would  be  found,  and  by  closing  them 
the  efficiency  of  the  process  would  be  increased.1 

1  An  excellent  series  of  articles,  entitled  "  Notes  on  Sampling,"  was  published  in  the  Mining  Reporter 
(Denver),  Oct. 24,  Nov.  28,  Dec.  5, 12\  19  and  T6,  1901  ;  Jan.  16,  23  and  Feb.  6,  1902. 


292  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

SAMPLING. 

THEORY. — In  theory  the  sampling  of  ore  consists  in  a  system  of  averag- 
ing, so  that  out  of  a  large  lot,  say  50  or  100  tons,  or  even  a  ship's  cargo  of 
S,500  tons  or  more,  a  small  amount,  e.g.,  500  g.  or  1  kg.,  which  is  further 
reduced  by  the  analytical  chemist  to  1  g.,  may  be  obtained,  which  is  per- 
fectly representative  of  the  whole  lot.  That  this  can  be  done  with  much 
exactness  is  proved  by  the  concordance  of  the  results  of  sampling  the  same 
lot  of  ore  by  two  or  more  different  methods.  Whatever  method  of  sampling 
be  employed,  the  principle  consists  of  the  reservation  of  a  certain  proportion 
of  the  ore  in  different  stages  of  the  process.  Its  success  depends  upon 
taking  a  large  proportion  of  the  ore  from  many  different  places  in  the  early 
stages,  and  the  thoroughness  of  the  mixture  of  the  particles  effected  in  the 
later.  This  mixture  is  accomplished  first  by  simply  crushing  the  ore,  and 
afterward,  as  the  reduction  in  bulk  progresses,  by  turning  it  over  by  shovel- 
ing, or  by  mechanical  devices. 

Supposing  a  lot  of  100  tons  of  ore  consisting  of  pieces  of  mixed  blende 
and  quartz,  all  of  3  in.  diameter,  were  to  be  sampled,  the  conventional  method 
is  to  reserve  every  tenth  shovelful  in  unloading  the  railway  cars  or  wagons, 
whence  there  results  a  first  sample  of  10  tons,  or  10%  of  the  original  quan- 
tity. This  sample  being  so  large  and  having  been  taken  at  regular  intervals 
in  the  discharge  of  the  ore,  the  same  proportion  from  all  parts,  may  be 
assumed  to  be  thoroughly  representative  of  the  whole,  which  is  the  case  as 
demonstrated  by  experience.  If  now  the  aforesaid  sample  were  to  be  re- 
duced further  in  the  same  manner,  without  any  intervening  steps,  the  final 
result  would  be  one  shovelful  or  one  piece,  which  might  or  might  not  be 
representative  of  the  original  ore,  according  to  the  uniformity  of  the  latter ; 
in  all  probability  it  would  not  be  representative,  the  error  accumulating  with 
each  successive  cutting  out.  Consequently,  the  theory  of  averages  demands 
a  breaking  up  of  the  first  sample  into  smaller  pieces  before  reducing  it  in 
bulk  any  further. 

The  idea  may  be  illustrated  by  supposing  that  we  had  a  mixture  of  9,000 
white  marbles  and  1,000  red  ones,  which  it  was  desired  to  sample.  By 
taking  one  tenth  of  them  at  regular  intervals,  precisely  the  same  quantity 
each  time,  we  should  probably  obtain  900  white  and  100  red.  A  second  cut- 
ting would  give  90  and  10  respectively,  if  the  result  chanced  to  be  perfect, 
while  the  third  would  give  nine  and  one.  A  fourth  would  necessarily  give 
either  one  white  marble  or  one  red  one,  but  in  either  case  the  result  would 
be  incorrect.  If,  however,  the  nine  white  and  one  red  had  been  each  broken 
into  tenths  and  the  pieces  had  been  thoroughly  mixed  the  averaging  might 


SAMPLING    AND   VALUATION    O.F    OliES.  293 

have  gone  on  with  as  slight  chance  of  error  as  at  the  third  cutting.  It  would 
have  been  still  better  if  they  had  been  broken  before  the  third  cutting.  If 
these  figures  were  increased  many  fold  the  conditions  would  be  somewhat 
analogous  to  those  in  sampling  a  lot  of  lump  ore. 

Crushing  Required. — The  size  to  which  a  lot  of  ore  should  be  broken 
before  each  cutting  out,  in  order  to  make  it  possible  to  obtain  a  correct 
average,  may  be  calculated  mathematically.  Such  a  calculation  is  based  on 
the  principle  that  a  certain  ratio  between  the  weight  of  the  sample  and  the 
size  of  the  largest  particle  having  been  assumed,  it  shall  be  maintained 
through  every  stage  of  the  operation,  because  the  volumes  and  weights  of 
pieces  of  the  samekind  of  ore  are  to  each  other  as  the  cubes  of  their  diameters. 
Most  of  the  calculations  of  this  kind  that  have  been  made  have  been  for  gold 
and  silver  bearing  ores,  which  owing  to  the  more  irregular  distribution  of 
their  values  are  more  difficult  to  sample  correctly  than  an  ordinary  zinc  or 
lead  ore.  However,  a  couple  of  examples  of  such  a  calculation  will  serve  to 
illustrate  the  principle. 

Reed  reckons1  that  with  a  silver  ore  averaging  50  oz.  per  2,000  lb.,  con- 
taining pieces  as  high  as  300  oz.  per  2,000  lb.,  in  cutting  down  from  100 
tons  to  10  tons,  the  pieces  of  ore  may  be  as  large  as  cocoanut  size;  from 
10  tons  to  one  ton,  orange  size;  from  one  ton  to  0-1  ton,  walnut  size;  from 
0-1  ton  to  6  lb.,  pea  size;  and  from  5  lb.  to  0-5  lb.,  fine  enough  to  pass  a 
20-mesh  sieve.  Argall  states2  that  in  sampling  rich  gold  ores  with  auto- 
matic machines  accurate  results  are  obtained  when  the  sample  cut  out  is 
20%  of  the  weight  of  the  ore  when  the  average  size  of  the  ore  is  1  in.,  1-25% 
when  the  size  of  the  ore  is  0-25  in.,  0-0785%  when  the  size  of  the  ore  is 
0-0625  in.  (8-mesh),  and  0-005%  when  the  size  of  the  ore  is  0-0171  in. 
(30-mesh).  In  sampling  material  of  8-mesh  size,  therefore,  a  cutting  out 
of  157  lb.  from  20,000  lb.  should  be  accurate,  although  in  practical  work  a 
somewhat  larger  proportion  would  be  taken  as  a  matter  of  extra  pre- 
caution. 

In  sampling  ores  for  blast  furnace  smelting,  it  is  objective  to  avoid 
breaking  the  pieces  smaller  than  2-5  to  3  in.  size  any  more  than  is  abso- 
lutely necessary,  since  that  size  is  the  best  for  the  operation  of  the 
furnace.  Nothing  of  that  kind  has  to  be  considered  in  sampling  a  zinc  ore, 
which,  if  it  is  to  be  reduced  by  the  Belgian  or  Rhenish  process,  must  be 
anyway  crushed  finely  enough  to  permit  of  it  being  cut  down  directly  to  a 
sample  of  small  bulk.  The  major  part  of  the  ore  received  by  the  zinc  smelter 
is  generally  a  concentrated  product,  already  fine  and  mixed  to  a  rather  uni- 

% 

1  School  of  Mines  Quarterly,  VI,  357.  in  Colorado  "  read  before  the  Institution  of  Mi- 

a  In  a  paper  on  "  Sampling  and  Dry  Crushing        ning  and  Metallurgy,  Feb.  20,  1902. 


PRODUCTION  AND  PROPERTIES  OF  ZINC. 

form  composition,  so  that  a  comparatively  small  proportion  taken  out  by  a 
single  cutting  will  afford  an  accurate  sample.  If  the  material  were  abso- 
lutely uniform  a  random  grab  sample  would  be  quite  sufficient,  but  that 
condition  is  one  that  is  hardly  to  be  relied  upon. 

The  zinc  smelter  does  not  therefore  generally  have  to  consider  the  more 
elaborate  systems  of  sampling  that  are  necessary  with  ores  of  more  variable 
character  and  less  uniform  composition,  but  in  this  connection  it  is  well 
to  describe  briefly  the  methods  employed  in  other  branches  of  metallurgy, 
which  may  be  modified  to  suit  the  particular  conditions.  The  sampling 
of  ore  and  other  products  may  be  done  either  by  hand  or  mechanically,  or 
by  a  combination  of  both  methods.  Mechanical  sampling  is  the  cheaper  and 
the  more  accurate,  but  sampling  by  hand  is  still  employed  to  a  consider- 
able extent  and  is  often  necessary  in  determining  the  value  of  occasional 
lots  of  material  for  which  the  means  for  mechanical  sampling  might  be 
inconvenient  or  unavailable. 

SAMPLING  BY  HAND. — The  method  which  is  the  cheapest,  when  the  ore 
does  not  have  to  be  crushed  for  another  purpose,  and  at  the  same  time  is  as 
efficient  as  any  other,  with  the  further  advantage  that  it  can  be  performed 
satisfactorily  by  inexperienced  men,  is  known  as  fractional  selection.  It 
consists  merely  in  shoveling  over  a  pile  of  ore,  putting  aside  an  aliquot  part, 
say  every  fifth  or  every  tenth  shovelful.  This  may  be  done  as  the  cars  or 
wagons  are  being  unloaded.  The  chief  precautions  to  be  observed  are  to 
shovel  always  from  the  floor  and  work  gradually  into  the  pile  from  one  or 
more  points  of  attack — i.e.,  avoid  shoveling  around  the  pile  at  random, 
which  might  result  in  two  shovelfuls  reserved  for  the  sample  being  taken 
from  about  the  same  place  in  the  pile. 

As  in  other  methods  of  sampling,  the  percentage  of  the  ore  which  may 
safely  be  reserved  in  the  first  cutting  out  depends  upon  the  fineness  and 
the  uniformity  of  the  mixture.  If  the  ore  be  very  fine,  two  or  more  cuts 
may  be  made  before  further  crushing,  but  the  ore  should  be  well  mixed  each 
time  before  doing  so.  Otherwise  it  should  be  crushed  finer  before  making 
the  second  cut,  and  so  on.  For  the  fine  crushing  of  small  samples  ma- 
chines of  the  coffee-mill  type  are  generally  employed.  When  the  sample 
has  been  reduced  to  a  small  quantity,  say  200  lb.,  the  further  cutting  down 
is  best  done  by  means  of  a  grid  or  riffle  sampler,  or  the  modification  of  it 
which  is  known  as  Jones'  sampler. 

The  sample  grinder  shown  in  Fig.  55  has  a  muller  at  the  head  of  a  vertical 
shaft,  which  is  revolved  in  close  proximity  to  an  annular  die  forming  a 
continuation  of  the  hopper  into  which  the  ore  is  fed.  Below  the  hopper 
there  is  a  cylindrical  housing,  which  confine?  the  crushed  ore  and 


SAMPLING   AND   VALUATION    OF   ORES. 


295 


it  through  two  spouts,  below  which  pans  are  placed  to  catch  it.  -The  degree 
of  crushing  is  regulated  by  raising  or  lowering  the  muller  by  means  of  the 
hand  wheel,  which  controls  the  lever  on  which  the  shaft  is  stepped.  The 
machine  shown  in  Fig.  52  has  tight  and  loose  pulleys  16X4-5  in.,  weighs 


L 


FIG.  55. — SAMPLE  GRINDER. 


775  Ib.  (900  Ib.  boxed  for  shipment)  and  requires  3  h.  p.     These  machines 
are  driven  at  150  r.  p.  m.     They  cost  about  $100,  f .  o.  b.  makers'  works. 

Grid  or  Riffle  Sampler. — The  grid,  or  riffle,  sampler  consists  of  a  series  of 
riffles  alternating  with  the  same  number  of  open  spaces,  the  width  of  the 
riffles  and  open  spaces  being  equal,  1  in.  width  being  a  common  dimension. 
The  fine  ore  being  fed  in  an  even  sheet  by  means  of  a  tray  of  the  same  width 
as  the  grid  over  all,  the  tray  being  drawn  longitudinally  over  the  riffles,  one 


296 


PRODUCTION   AND   PROPERTIES    OP   ZINC. 


half  will  fall  through  the  open  spaces  into  another  tray  placed  underneath, 
while  the  other  half  will  be  caught  in  the  riffles. 

Jones'  Sampler. — This  apparatus,  which  is  shown  in  Figs.  57  to  59,  is  an 
improvement  on  the  simple  riffle  and  tray,  but  works  on  the  same  principle. 
It  consists  of  a  series  of  narrow,  triangular  hoppers,  which  are  joined  side 
by  side  in  such  a  way  that  alternate  divisions  point  in  opposite  directions, 
the  whole  being  supported  by  a  wooden  frame.  The  sample  is  distributed 
over  the  top,  just  as  in  the  case  of  the  simple  riffle,  .and  the  cuttings  are 
received  in  appropriate  pans.  Four  pans  should  be  provided,  two  of  which 


Kiffles  made  of  No.  iO  steel 


M  II  III  I  I  I 


111 


^1 

Pan  4>£'  deep 

made  of  No.  1C 

steel,  turned  over 

Vis  wire  nt  riin 

<o" 

I 

*"  3/'s  wire 

FIG.  56. — RIFFLE  SAMPLER. 


will  be  in  use  at  a  time.    This  apparatus  is  easily  handled  and  cleaned,  and 
permits  of  quick  and  accurate  work. 

Quartering. — The  first1  sample  may  also  be  cut  down  by  the  time- 
honored  method  of  quartering,  which  consists  in  first  shoveling  the  ore  into 
a  large  ring,  each  shovelful  being  thrown  on  the  ring  in  regular  order  from 
left  to  right,  or  vice  versa.  The  fine  ore  remaining  on  the  floor  inside  the 
ring  is  swept  to  the  center  and  is  carefully  gathered  up  and  distributed 
evenly  all  around  the  ridge  of  the  ring.  The  ore  in  the  ring  is  then  shoveled 
into  the  center  in  such  a  way  as  to  form  a  true  cone.  In  doing  this,  it  is 
essential  to  shovel  gradually  around  the  ring,  always  moving  in  the  same 
direction,  and  throw  each  shovelful  precisely  on  the  top  of  the  cone,  so  that 


1  By  this  is  meant  the  sample  obtained  in 
reserving  a  certain  percentage  of  the  shovel- 
fuls in  the  first  handling  of  the  ore.  The 


direct  quartering  of  a  large  lot  of  ore,  say 
50  or  100  tons,  would  be  too  cumbersome  a 
process. 


SAMPLING   AND   VALUATION    OF   ORES. 


297 


the  particles  of  ore  will  distribute  themselves  equally  over  the  pile.     The 
object  of  ringing  and  coning  is  to  mix  the  ore  thoroughly. 

The  cone  having  been  formed,  it  is  pulled  down  with  the  aid  of  long-handle, 
round  point  shovels,  beginning  near  the  top  of  the  cone,  and  walking  around 
it,  working  it  down  from  center  to  periphery  until  it  becomes  a  truncated 


fP 


No.  20  Iro 


'drop 


Fig. 


FIGS.  57  TO  59. — JONES'  SAMPLEK. 

Section  on  line  AB  of  Fig.  58.     Fig.   58  :     Plan.     Fig.   39  : 


Charging  pan. 


cone  about  6  in.  high.  This  is  marked  off  into  quarters  by  means  of  a  rod 
with  a  sharp  edge  and  the  alternate  quarters  are  shoveled  away,  whence  the 
name  "quartering/'  Care  must  be  taken  to  sweep  away  the  dust  from  the 
floor  where  the  quarters  have  been  removed.  The  remaining  quarters  are 
then  ringed  out  and  coned  as  before,  and  quartered  down  until  the  sample 


298  PRODUCTION    AND    PROPERTIES    OE    ZINC. 

amounts  to  50  or  100  Ib.,  after  which  the  further  reduction  is  generally  done 
by  riffling.  It  is  customary  to  employ  two  men  at  quartering,  in  which 
case  they  shovel  on  the  ring  and  cone  diametrically  opposite  to  each  other. 
They  ought  to  sample  2,000  Ib.  down  to  5  Ib.  in  about  two  hours.  The 
method  of  sampling  by  quartering  is  subject  to  serious  errors,  and  although 
still  employed  in  numerous  works,  has  been  discarded  in  others  as  being 
quite  unreliable.  Some  metallurgists  do  not  permit  its  use  for  any  pur- 
pose, not  even  in  the  assay  office,  the  final  reductions  being  performed  en- 
tirely by  riffling.  The  objections  to  the  method  of  quartering  are  sound, 
and  therefore  it  is  not  to  be  recommended. 

MECHANICAL  SAMPLING. — Where  the  ore  is  discharged  by  gravity  through 
a  chute,  it  may  be  sampled  mechanically  by  means  of  some  device  which 
will  take  out  a  part  of  the  stream  or  will  divert  the  whole  stream  at  regular 
intervals.  The  latter  method  is  the  sounder  in  principle.  The  objection  to  the 
mechanical  samplers  which  divert  a  part  of  the  stream  is  that  the  ore  is  apt 
to  be  not  uniformly  mixed.  If  it  slides  down  an  inclined  chute  the  fine 
particles  either  will  remain  on  the  bottom,  while  the  coarse  rise  to  the  top 
and  often  bound  along  the  surface,  or  the  fine  particles,  naturally  moving  the 
more  slowly,  will  be  pushed  to  the  sides,  while  the  coarse  pass  rapidly  down 
the  center.  The  metallic  minerals  being  more  brittle  than  the  quartzose  or 
calcareous  gangue  minerals,  the  fines  of  an  ore  are  usually  richer  than  the 
lumps  and  consequently  the  stream  is  of  uneven  grade. 

In  the  other  class  of  mechanical  samplers  the  entire  stream  of  ore,  good 
and  bad,  is  cut  out  at  regular  intervals,  the  amount  taken  being  regulated 
by  the  frequency  of  the  deflections  and  the  length  of  time  they  last.  This 
is,  therefore,  nothing  more  than  a  mechanical  system  of  fractional  selection. 
The  machines  of  this  class  which  are  chiefly  in  use  in  the  United  States  are 
those  of  Brunton,  Bridgman,  Constant  and  Vezin.  For  simplicity,  cheap- 
ness and  efficiency  that  of  Vezin  is  preeminent. 

The  Vezin  sampler  consists  of  two  truncated  cones  of  sheet  steel,  joined 
together  at  their  bases,  thus  producing  an  apparatus  in  shape  something  like 
a  can  buoy.  The  upper  cone  has  a  scoop,  of  which  the  horizontal  section 
has  the  shape  of  a  sector  of  a  circle.  The  machine  is  fixed  on  a  vertical 
spindle,  by  which  it  is  revolved.  It  is  placed  so  that  the  scoop  at  each  revo- 
lution cuts  through  the  stream  of  ore  to  be  sampled.  The  ore  thus  caught 
slides  down  into  the  lower  cone  and  thence  through  a  spout  to  a  receiving 
bin.  The  upper  cone,  which  carries  the  scoop,  serves  simply  to  prevent  any 
stray  pieces  of  ore  from  falling  into  the  lower  one.  It  is  preferable  to 
present  the  ore  to  the  scoop  by  an  inclined  chute,  say  at  58°,  rather  than 
as  a  stream  falling  vertically.  The  frequency  of  the  samples  depends  upon 


SAMPLING    AND   VALUATION    OF    ORES. 


299 


the  number  of  revolutions  of  the  scoop,  10  r.  p.  m.  being  an  ordinary  speed. 
The  size  of  the  sample  depends  upon  the  relation  of  the  scoop  to  the  circle 
of  which  it  is  a  sector.,  e.g.,  if  the  diameter  of  the  circle  be  24  in.  and  it  be 
desired  to  cut  out  one  tenth  the  sector  must  be  3-54  in.  at  the  arc.  The 
width  of  the  sector,  however,  must  always  be  four  times  the  diameter  of  the 
largest  piece  of  ore.  When  the  ore  to  be  sampled  is  so  fine  that  it  may  be 
cut  down  to  a  small  percentage  without  any  further  crushing,  two  samplers 
are  commonly  arranged  in  series,  a  suitable  mixing  device  being  interposed 


FIGS.  60  AND  61. — ELEVATIONS  OF  VEZIN  AUTOMATIC  SAMPLER  AND 

ELEVATOR  HEAD. 

between  the  two.  The  second  sampler  thus  receives  the  sample,  thoroughly 
mixed,  which  is  cut  out  by  the  first. 

The  Vezin  sampler  and  its  method  of  installation  are  shown  in  the  ac- 
companying engravings.  The  machine  is  supplied  by  the  F.  M.  Davis  Iron 
Works  Co.,  of  Denver,  Colo.,  but  can  be  built  in  any  machine  shop  from 
drawings  which  can  be  obtained  from  its  inventor,  H.  A.  Vezin,  of  Denver, 
Colo.  The  cost  of  a  machine  installed  is  usually  about  $200. 

Arrangement  of  Mechanical  Samplers. — The  installation  of  any  me- 
chanical sampling  apparatus  involves  an  elevation  of  the  whole  quantity  of 


PRODUCTION    AND   PROPERTIES    OF    ZINC. 

ore  in  order  to  establish  a  falling  stream  in  which  the  machine  may  be 
interposed.  If  the  ore  has  to  be  crushed  it  will  in  all  probability  have  to 
be  raised  anyway  in  order  to  screen  it.  A  belt  and  bucket  elevator  is  the 
means  usually  employed.  With  such  an  arrangement  the  elevation  of  a 
good  many  tons  of  ore  to  a  considerable  height  is  by  no  means  expensive. 
Even  under  unfavorable  conditions  the  cost  of  elevation  to  30  ft.  ought  not 
to  exceed  0-5c.  per  ton.  In  the  case  of  a  zinc  ore  already  crushed  very  fine, 


U 


FIGS.  62  AND  63. — ELEVATION  AND  PLAN  SHOWING  ARRANGEMENT  OF 
VEZIN  AUTOMATIC  SAMPLERS  ix  DUPLICATE. 


an  automatic  sampling  system  would  consist  simply  of  a  belt  and  bucket 
elevator  and  the  cutting  out  machines.  However,  unless  it  were  necessary 
to  elevate  the  ore  to  storage  bins,  or  for  some  other  purpose  in  which  the 
sampling  process  intervened  mertly  as  an  incident,  the  cost  of  sampling 
mechanically  in  the  manner  suggested  above  might  be  more  than  that  of 
sampling  by  hand  as  the  wagons  were  unloaded.  If  on  the  other  hand  the 
ore  had  to  be  elevated  anyway,  so  that  the  cost  of  handling  the  ore  could 


SAMPLING    AND   VALUATION    OF    ORES. 


301 


be  charged  properly  to  another  process,  the  cost  of  sampling  mechanically 
would  be  cheaper  than  by  hand.  In  a  works  where  a  considerable  quantity 
of  ore  has  to  be  sampled,  the  cost  per  ton  is  insignificant. 


FIGS.  64-66. 

ARRANGEMENT  OF  VEZIN 
AUTOMATIC  SAMPLERS  IN- 
DUPLICATE. 


FIG.  64. —  PLAN. 

FIG.  65. — SIDE  ELEVATION. 

FIG.  66. — FRONT  ELEVATION. 


DETERMINATION  OF  MOISTURE. — In  buying  ores  it  is  important  to  deter- 
mine the  percentage  of  hygroscopic  moisture  which  they  contain,  especially 
if  they  be  raw  concentrates,  which  are  always  wet,  while  even  calcined  ores 


302  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

will  contain  as  much  as  \%  of  water  if  they  have  been  exposed  to  the 
atmosphere  for  any  considerable  length  of  time.  The  moisture  sample 
should  be  taken  immediately  after  the  weighing  of  the  ore.  A  grab  sample 
is  made  to  answer  for  this  purpose.  The  method  is  conceded  to  be  inaccu- 
rate, but  by  common  agreement  it  is  accepted. 

A  rather  large  sample  should  be  taken  for  moisture  determination.  It 
should  be  at  least  sufficient  to  permit  two  portions  of  50  oz.  each  to  be 
weighed  out,  and  preferably  two  of  100  oz.  each.  By  the  metric  system, 
1  or  2  kg.  are  convenient  weights.  The  sample  should  be  put  into  a  tin  can, 
with  closely  fitting  cover,  immediately  upon  taking  it  and  should  not  be 
exposed  until  it  is  to  be  weighed  out. 

The  scales  commonly  used  are  the  Fairbanks  or  Howe,  specially  made  for 
this  purpose,  which  are  graduated  in  ounces  and  half  ounces,  or  ounces  and 
twentieths,  and  enable  the  percentage  to  be  read  directly.  The  kind  gradu- 
ated in  ounces  and  twentieths  reads  to  0-1%  when  50  oz.  are  weighed  out; 
it  costs  $15.  An  excellent  balance  for  moisture  determinations,  and 
other  experimental  work  in  a  metallurgical  laboratory,  is  the  Troemmer 
solution  scale,  costing  $17,  which  is  graduated  to  grams,  weighs  up  to  20 
kg.,  and  is  extremely  accurate. 

The  moisture  samples  having  been  weighed  out  (they  should  be  made  in 
duplicate)  are  dried  in  a  sheet  iron  closet,  heated  by  steam,  or  in  any  con- 
venient manner,  in  which  a  constant  temperature  of  100°  C.  can  be  main- 
tained. The  closet  should  have  shelves  on  which  the  pans  containing  the 
samples  can  be  placed.  In  order  to  facilitate  the  drying,  the  samples  should 
be  stirred  with  a  spatula  from  time  to  time.  The  complete  elimination  of 
moisture  can  be  determined  by  holding  a  cold  watch  glass  over  the  sample 
for  a  moment  or  two ;  the  absence  of  condensed  vapor  will  indicate  that  the 
ore  has  ceased  to  give  off  any  and  is  dry.  The  sample  is  then  to  be  removed 
and  weighed  again.  The  percentage  of  moisture  in  the  original  ore  will  be 
calculated  from  the  loss  of  weight. 

In  determining  the  moisture  of  lump  ore  the  latter  should  be  broken  up 
on  the  bucking  plate  to  about  pea  size,  before  weighing  out  the  sample  to 
be  dried. 

ORE  SAMPLING  IN  EUROPE. — Zinc  ore  from  Sardinia,  Spain,  Algeria  and 
elsewhere  is  received  at  Antwerp  chiefly  in  steamships  of  2,500  to  3,000  tons 
cargo  capacity.  Having  been  generally  calcined  (if  calamine)  or  roasted 
(if  blende)  at  the  mines  where  it  was  produced,  it  arrives  at  Antwerp  in 
the  condition  of  fines.  It  is  unloaded  into  railway  cars  on  the  wharf, 
whence  it  is  despatched  directly  to  Li&ge,  Stolberg  and  elsewhere.  The 
method  of  discharging  cargoes  is  crude.  The  ore  is  hoisted  from  the  ship's 


SAMPLING    AND    VALUATION    OF    ORES.  303 

hold  in  bags  or  baskets,  which  are  weighed  separately  by  means  of  beam 
scales.  The  railway  wagons  carry  about  10,000  kg.  each  and  a  basket  of 
ore  weighs  about  50  kg.  Generally  eight  baskets  per  wagon,  or  one  in  25, 
are  reserved  as  a  sample,  the  sample  basket  being  chosen  at  random  by  agree- 
ment of  the  representatives  of  the  buyer  and  seller,  or  more  commonly  the 
agent  to  whom  both  parties  have  entrusted  their  interests  in  this  part  of  the 
business.  The  sample  baskets  are  carried  to  a  shed,  where  their  contents 
are  mixed,  quartered  down  and  divided  into  three  parts  for  analysis  in  the 
usual  manner.  Settlements  are  made  in  Antwerp  on  that  basis. 

VALUATION  OF  ZINC  ORES. 

There  are  various  formulae  employed  by  European  smelters  to  determine 
the  value  of  zinc  ore,  all  of  them  being  based  on  the  London  quotation  for 
spelter,  the  tenor  of  zinc  in  the  ore,  the  loss  of  zinc  in  smelting  and  the 
cost  of  carriage  and  smelting.  The  factors  assumed  to  represent  loss  in 
treatment  and  cost  of  treatment  are  of  course  arbitrary,  and  vary  according 
to  the  character  of  the  ore  and  requirements  of  individual  smelters.  The 
price  of  zinc  at  Antwerp,  Liege,  Hamburg,  Breslau  and  elsewhere  is  gov- 
erned by  the  London  market.  The  price  of  zinc  at  London  is  accepted  as 
reported  in  the  "London  Commercial  Beport"  of  the  Public  Ledger,  or  other- 
wise as  may  be  agreed,  the  average  price  of  the  month  of  the  ship's  arrival 
being  commonly  taken.  The  terms  of  settlement  are  also  a  matter  of  mutual 
agreement,  but  the  buyers  generally  offer  80%  of  the  value  of  the  consign- 
ment on  ship's  arrival,  and  the  remainder  after  agreement  of  weights,  assays 
and  the  basis  price  of  spelter. 

In  the  United  States  there  is  comparatively  little  ore  sold  by  the  use  of 
formulae  which  introduce  all  the  factors  affecting  the  value  of  the  mineral, 
but  there  is  an  increasing  tendency  toward  the  adoption  of  that  method. 
Whether  the  transactions  are  based  on  an  arbitrary  bid  or  on  a  sliding  scale, 
however,  the  governing  factor  is  the  price  of  prime  Western  spelter  at  St. 
Louis. 

The  determination  of  the  value  of  zinc  ore  by  means  of  a  formula  which 
constitutes  an  automatic  sliding  scale,  based  on  the  tenor  of  zinc  in  the  ore 
and  its  value  in  that  crude  form,  is  by  all  means  the  fairest  and  generally 
the  most  satisfactory  method  to  both  seller  and  buyer. 

CUSTOM  OF  THE  JOPLIN  DISTRICT. — In  the  Joplin  district  of  the  United 
States  the  buying  and  selling  of  ore  is  customarily  effected  by  weekly  trans- 
actions. The  old  method  of  completing  these  is  still  in  use  to  a  considerable 
extent.  The  smelters  who  consume  the  Joplin  ores  have  agents  in  the  dis- 


304  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

trict,  who  visit  weekly  the  various  mills  and  after  a  visual  examination  of 
the  concentrated  ore  displayed  in  the  bins  make  a  bid  of  so  much  per  ton 
for  the  week's  output.  The  miner  sells  to  the  highest  bidder  and  trans- 
actions are  settled  by  cash  payment  on  Saturday.  The  smelter's  bid  is  for 
the  ore  in  the  mill  bins,  so  the  cost  of  carting,  usually  25  to  50c.  per  ton, 
falls  on  him.  Another  local  peculiarity  is  that  no  determination  is  made 
of  the  moisture  contents  of  the  ore  and  the  settlement  is  made  on  the  wet 
weight,  though  if  the  ore  be  excessively  wet  a  certain  arbitrary  deduction  in 
weight  may  be  made  by  mutual  agreement.  Ordinarily  the  coarse  concen- 
trates of  the  district  contain  2  to  3%  water,  while  the  slime  (locally  called 
"sludge")  holds  10  to  18 %  when  fresh.  This  crude  system  of  buying  and 
selling  ore  is  the  outgrowth  of  the  local  conditions  of  mining  and  smelting, 
in  neither  of  which  has  skilled  technical  advice  and  supervision  been  em- 
ployed to  a  considerable  extent  until  recently. 

Since  1899  blende  concentrates  have  been  settled  for  in  the  Joplin  district 
to  some  extent  upon  the  basis  of  their  tenor  in  zinc,  as  shown  by  sample  and 
assay.  The  system  of  sampling  employed  consists  in  taking  a  few  shovel- 
fuls of  the  ore  after  it  has  been  loaded  in  the  railway  car,  which  are  mixed 
together  and  quartered  down  to  about  two  pounds.  This  is  divided  into 
three  parts,  one  of  which  is  assayed  by  the  buyer  and  one  by  the  seller,  the 
third  being  reserved  against  accident  or  disagreement.  If  the  assays  agree 
within  a  few  tenths  of  a  per  cent,  the  average  is  taken  as  the  basis  of  settle- 
ment. Moisture  is  determined  in  the  usual  manner.  The  selling  of  ore 
on  an  assay  basis  has  led  to  an  improvement  in  the  grade  of  the  product  of 
those  miners  who  have  adopted  the  custom  and  obtain  thereby  a  guide  as 
to  the  efficiency  of  their  mill  work.  Sometimes  the  ore  is  sampled  in  the 
bins  at  the  mill  by  boring  with  a  tube  through  the  bed  of  ore  in  numerous 
places. 

The  calamine  ores  of  Aurora  and  Granby  are  not  yet  sold  upon  an  assay 
basis.  They  fetched.  $10@$14  per  ton  f.  o.  b.  cars  in  1901,  their  tenor  in 
zinc  ranging  from  40  to  48%.  Their  value  fluctuates  more  or  less  accord- 
ing to  the  price  of  spelter.  In  1899  when  spelter  was  quoted  at  6c.  calamine 
assaying  about  44%  Zn  commanded  $25  per  ton  f.  o.  b.  cars. 

SLIDING  SCALES. — Contracts  for  ore  are  frequently  made  in  Europe,  par- 
ticularly for  standard  ores  of  well-known  composition,  on  a  sliding  scale 
up  and  down  from  an  arbitrary  basis.  In  such  cases  a  certain  value  is  estab- 
lished for  a  certain  grade  of  ore  at  a  certain  price  for  spelter  at  London  and 
that  basis  price  is  changed  to  correspond  with  fluctuations  in  the  price 
of  the  metal  in  the  London  market,  an  addition  or  deduction  being  made 
for  each  unit  of  zinc  above  or  below  the  standard.  This  method  is  illus- 


SAMPLING   AND   VALUATION   OF   ORES.  305 

t  rated  in  the  following  offer  for  blende  concentrates,  which  was  made  by 
a  Belgian  smelter  in  the  early  part  of  1902.  A  basis  price  of  132-5  fr.  per 
1,000  kg.  of  ore  ex  ship  at  Antwerp,  when  spelter  is  £18  per  1,000  kg.  at 
London,  is  established.  For  each  unit  of  zinc  below  50  there  is  a  deduction 
of  5  fr.  ;  for  each  unit  above  50  the  price  is  increased  4  f  r.  ;  consequently 
the  value  of  ore  assaying  60%  Zn  would  be  172-50  fr.  when  spelter  is  at 
£18,  London.  An  addition  or  deduction  of  12-50  fr.  is  made  to  or  from 
the  basis  price  for  each  variation  of  £1  in  the  price  of  spelter.  Thus  an  ore 
assaying  50%  Zn  would  be  worth  120  fr.  at  £17,  while  an  ore  assaying 
60%  Zn  would  be  worth  160  fr.  The  London  quotation  of  spelter  in 
pounds  sterling  per  2,240  Ib.  is  divided  by  1,015  to  obtain  the  equivalent 
per  1,000  kg.  For  a  unit  of  iron  in  excess  of  4%  a  deduction  of  3  fr.  is, 
made  from  the  value  of  the  ore;  for  each  unit  in  excess  of  5%  the  deduction 
is  5  fr.  Such  contracts  involve  naturally  the  cost  of  smelting  and  the  loss 
in  treatment,  but  it  is  extremely  difficult  to  formulate  them  so  that  they 
will  be  equally  fair  to  both  parties  in  all  fluctuations  of  the  price  of  metal 
and  variations  in  the  grade  of  the  ore. 

The  effect  of  the  varying  factors  which  determine  the  value  of  an  ore  is 
allowed  for  in  numerous  formulae,  which  greatly  simplify  the  calculation. 
These  formula?  represent  algebraically  the  percentage  of  zinc  in  the  ore,  the 
loss  in  smelting,  the  market  price  of  spelter  at  London,  Breslau  or  St.  Louis 
and  the  cost  of  carriage  on  ore,  smelting  and  the  smelter's  profit.  Some  of 
these  formulae  are  analyzed  as  follows  : 

I.     Buyers  of  zinc  ore  in  Antwerp  often  use  the  formula 


V  — 


-  TL)  X  (P  -  2-50) 


10 
in  which 

V  =  value  of  ore  in  francs  per  1,000  kg. 
T  =  units  of  zinc  in  ore. 

L  =  loss  in  treatment  expressed  decimally  or  fractionally. 
P  =  price  of  spelter  in  francs  per  100  kg. 

S  =  cost  of  carriage  and  smelting,  and  smelter's  profit,  commonly 
referred  to  as  the  "  returning  charge." 

If  the  price  of  spelter  be  £18  at  London  and  exchange  25-20,  P  will  be 
44-68.  Assuming  T=50,  L=0-20,  and  S=60  fr.,  the  value  of  an  ore  assay- 
ing 50%  Zn  would  be  108-72  fr.  per  metric  ton  ex  ship  at  Antwerp. 

This  formula  introduces  the  number  of  units  of  zinc  recoverable  in  smelt- 
ing the  ore,  represented  by  the  expression  T—TL,  which  is  equivalent  to 
0-8  T.  The  market  price  of  spelter  is  represented  by  the  expression 
P  —  2-50,  in  which  P  is  the  equivalent  in  francs  per  100  kg.  of  the  London 
price  quoted  in  pounds  sterling  per  2,240  Ib.  ;  a  deduction  of  2-50  fr.  per 
100  kg.  is  made  to  cover  freight  on  spelter  from  the  works,  commissions, 


306  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

insurance,  etc.  Inasmuch  as  the  tenor  of  zinc  in  the  ore  is  represented  by 
units  of  10  kg.  each,  and  since  that  number  is  multiplied  by  the  value  of  10 
units  of  spelter,  it  is  necessary  to  divide  the  product  by  10  before  deducting 
the  returning  charge.  The  latter  will  vary  according  to  the  grade  and 
character  of  the  ore,  the  requirements  of  the  smelter,  etc.  It  will  be  rela- 
tively low  in  this  formula,  because  the  smelter  will  realize  a  profit  on  the 
zinc  recovered  over  and  above  what  he  pays  for  according  to  the  expression 


II.  Another  formula  introducing  a  modification  to  discriminate  between 
the  value  of  calamine  and  roasted  blende  is  the  following  : 

a  For  calamine  :  V  =  (0'95  P^°-8T)  -  S. 
b  For  roasted  blende  :  V  =  K™  *  xarsT-i)]  _  g> 

in  which  the  symbols  have  the  same  meaning  as  in  formula  No.  1.  The 
value  of  a  calamine  ore  under  the  same  conditions  as  in  formula  No.  1 
would  be  determined  by  formula  No.  2  to  be  109-78  fr.,  while  roasted  blende 
of  the  same  tenor  in  zinc  would  be  worth  105-54  fr. 

Formula  Ha  and  II&  are  identical  with  I,  save  that  the  expression 
0-95  P  is  substituted  for  P  —  2-50  to  allow  for  the  charges  on  the  spelter 
product,  and  an  additional  unit  is  deducted  from  0-8  T  in  the  case  of  the 
roasted  blende  to  compensate  for  the  lower  extraction  of  zinc  from  that  class 
of  ore. 

III.  In  Europe  at  the  present  time  zinc  ore  is  frequently  purchased  on 
a  sliding  scale  based  on  the  formula 

V  =  [0-95P  X^^]-S. 
in  which 

V  =  value  of  ore  per  ton  of  2,240  Ib.  ex  ship  at  Swansea,  Antwerp  or 

Hamburg. 
P  =  average  price  of  spelter  (good  ordinary  brands)  at  London  during 

month  of  delivery  of  the  ore. 

T  =  number  of  units  of  zinc  contained  in  the  ore  as  shown  by  assay. 
S  =  returning  charge. 

This  constitutes  a  scientific  and  equitable  basis.  The  discount  from  the 
London  price  of  the  metal  corresponds  more  or  less  to  the  cost  of  delivering 
at  London  the  smelter's  product  —  i.e.,  0-95  P  represents  the  value  of  the 
metal  at  the  works  where  produced.  The  expression  T  —  8  covers  the  loss 
in  smelting,  and  takes  into  account  the  proportionately  higher  loss  in  smelt- 
ing low  grade  ores.  If  T=60,  the  smelter  pays  for  86%%  of  the  zinc  in 
the  ore;  if  T=50,  Le  pays  for  84%.  The  costs  of  carriage  of  the  ore  from 
the  seaport  to  the  works,  the  cost  of  smelting  and  the  smelter's  profit  are 
covered  practically  by  the  returning  charge,  S,  inasmuch  as  there  will  be 


SAMPLING   AND  VALUATION    OF   ORES.  307 

little  or  no  margin  over  T — 8.  The  returning  charge  will  vary,  of  course, 
with  the  character  of  the  ore,  market  conditions,  etc.  In  1900,  a  bid  for 
raw  blende  assaying  60%  Zn  was  £3  10s.  per  2,240  Ib. ;  another  bid  made 
a  returning  charge  of  only  £3.  When  spelter  was  worth  £22  at  London,  a 
returning  charge  of  £3  10s.  made  the  value  of  60%  ore=£7  7s.  4d.  ex  ship 
at  Swansea,  Antwerp  or  Hamburg=$35-848  per  2,240  Ib.  (reckoning  ex- 
change at  $4-866)  =$32  per  2,000  Ib. 

This  formula  is  the  same  as  Ila,  save  that  the  percentage  of  zinc  paid  for 
in  the  ore  is  represented  by  T — 8  instead  of  0-8  T.  In  order  to  give  the 
value  of  the  ore  in  francs  per  metric  ton  it  would  be  made 

V  -       (0-95  P  X  (T  -  8)      _  « 
10 

in  which  P  is  the  value  of  spelter  in  francs  per  100  kg. 

In  order  to  obtain  the  value  of  ore  in  dollars  per  2,000  Ib.  the  modifica- 
tion of  the  formula  would  be 

[20(T-8)XP]-S, 
in  which  P  is  the  value  of  spelter  in  cents  per  pound. 

Inasmuch  as  so  high  a  percentage  of  zinc  is  paid  for  under  this  formula, 
the  returning  charge  has  to  be  made  large  enough  to  cover  all  costs,  besides 
the  smelter's  profit. 

IV.  Ore  buyers  in  Swansea,  Wales,  used  to  employ  a  rule,1  which  is  re- 
duced to  the  following  formula : 


in  which 

V  =  value  of  ore  per  2,240  Ib. 

W  =  percentage  of  ore  remaining  after  calcination,  expressed  decimally. 

P  =  price  of  spelter  per  2,240  Ib.  at  London,  less  £1. 

T  =  tenor  of  zinc  in  ore,  expressed  in  units,  j 

C  =  loss  in  calcination  expressed  in  unit*. 

S  =  smelting  charge,  considered  to  be  £2  10s. 

L  =  cost  of  calcination,  assumed  to  be  5s. 

Assuming  an  ore  assaying  40 %  Zn,  which  will  lose  30%  of  its  weight  in 
calcination,  its  value  when  spelter  is  worth  £17  at  London  will  work  out  by 
the  above  formula  as  follows  : 
40—1         39 

100-30  =  70  =  °'557' 

0-557  x  0-8  =  0-446. 

0-446-0-01  =  0-436. 

0.436  x  £16  =  £6.976  =  £6  19s  6d. 

£6  19s  6d  -£2  10s  =  £4  9s  6d. 

0'70  x  £4  9s  6d  =  £3  2s  8d. 

£3  2s  8d  -  5s  =  £2  17s  8d  =  net  value  of  the  ore  per  ton. 

1  H.  D.  Hoskold,  Trans.  Fed.  Inst.  Min.  Eng..  V,  i  and  ii,  93. 


308  PRODUCTION  AND  PROPERTIES  OF  ZINC. 

An  analysis  of  this  formula  shows  it  to  be  less  complicated  than  appears 
at  first  sight.  The  expression  (T — l)-f-(100 — C)  gives  the  percentage  of 
zinc  in  the  calcined  ore,  on  which  the  value  of  the  metal  is  calculated  and 
against  which  the  smelting  charge  is  deducted.  The  smelter  receives  an  al- 
lowance of  one  unit  and  pays  for  only  80%  of  the  remainder,  which  allows 
for  the  difference  in  loss  between  ores  of  different  grades  and  leaves  besides 
a  certain  margin  of  profit.  It  is  proper  to  make  a  fixed  deduction  from  the 
London  price  rather  than  a  percentage  deduction,  inasmuch  as  the  freight 
charges  at  least  remain  constant,  irrespective  of  the  selling  price.  The 
value  having  been  calculated  on  the  calcined  ore  the  result  must  be  reduced 
to  terms  of  raw  ore  by  considering  the  relation  between  the  weight  of  the 
raw  and  calcined  ore,  which  is  done  by  introducing  the  factor  W. 

V.    In  Upper  Silesia  calamine  used  to  be  bought  by  the  formula1 


V  — 


PX  0-66)  -  101. 


100 

in  which 

V  =  value  of  ore  per  100  kg. 

P  =  price  of  zinc  at  Breslau  per  100  kg.  less  0'5  mark. 

T  =  units  of  zinc  in  ore. 

If  spelter  be  worth  32-6  marks  per  100  kg.  at  Breslau,  which  is  equivalent 
to  approximately  £18  per  2,2-iO  Ib.  at  London,  the  value  of  an  ore  assaying 
20%  Zn  would  be  [(20X32-1X0-66)— 101] -HlOO=3-227  marks  per  metric 
centner=32-27  marks  per  metric  ton=$6-97  per  2,000  Ib.  Similarly,  the 
value  of  an  ore  assaying  10%  Zn  would  be  1-109  marks  per  centner^ 
11-09  marks  per  metric  ton=$2-40  per  2,000  Ib. 

In  the  case  of  blende  a  deduction  of  7-5  marks  per  metric  ton=$l-62 
per  2,000  Ib.  is  made  to  cover  the  cost  of  roasting. 

VI.  A  contract  for  blende  concentrates  produced  in  Joplin,  Mo.,  assay- 
ing about  60%  Zn  and  not  more  than  2%  Fe  was  effected  in  November, 
1899,  on  the  following  basis,  f .  o.  b.  mines : 

V=[16TX(P-0-20)]-S 
in  which 

V  =  value  of  ore  in  dollars  and  cents  per  2,000  Ib. 

T  =  units  of  zinc  in  ore. 

P  =  price  of  prime  Western  spelter  at  St.  Louis  in  cents  per  pound. 

S  =  charge  for  carriage  and  smelting  of  ore,  etc. 

In  this  formula  the  factor  16  represents  the  product  of  the  number  of 
pounds  in  a  unit,  namely  20,  by  the  assumed  percentage  of  recovery  of 
zinc  namely  0-80.  The  factor  S  varied  within  certain  limits,  according  to 

1Kosmann,  Oberschlesien,  sein  Land  und  seine  Industrie,  p.  153. 


SAMPLING   AND   VALUATION    OF   ORES.  309 

the  value  of  spelter  and  also  whatever  percentage  of  iron  there  might  be  in 
the  ore  over  2%.  P— 0-20  represented  the  value  of  spelter  at  the  works  in 
Kansas.  This  formula  is  substantially  the  same  as  No.  1. 

VII.  A  schedule  to  determine  the  price  of  ore,  known  as  the  Paxton 
scale,  was  adopted  in  1899  by  the  Missouri  and  Kansas  Zinc  Miners'  Asso- 
ciation, which  corresponded  to  the  formula 

V=700  P 
in  which 

V  =  value  of  ore  per  2,000  Ib.  assaying  60  %  Zn. 

P  =  value  of  prime  Western  spelter  at  St.  Louis  in  cents  per  pound. 

Thus  if  the  price  of  spelter  were  6c.  per  Ib.,  the  price  of  ore  would  be  $42 
per  ton;  with  spelter  at  5c.  per  Ib.  ore  would  be  $35,  and  so  on.  This 
formula  was  quite  impractical,  inasmuch  as  it  made  the  value  of»  zinc  in 
ore  bear  a  constant  relation  to  the  value  of  the  marketable  metal,  while  no 
account  was  taken  of  the  fact  that  the  cost  of  smelting  remains  unaffected 
by  fluctuations  in  the  value  of  the  metal,  wherefore  its  proportion  in  the 
cost  of  production  increases  as  the  cost  of  the  ore  goes  down.  For  example, 
if  the  cost  of  carriage,  smelting,  etc.,  be  $10  per  ton  of  ore  and  80%  of 
the  zinc  be  recovered,  2,000  Ib.  of  60%  ore  will  yield  960  Ib.  of  metal, 
which  at  6c.  per  Ib.  would  be  worth  $57-60.  The  cost  of  production  if  the 
ore  were  bought  according  to  the  schedule  of  the  Miners'  Association  would 
be  $42  for  ore,  plus  $10  for  freight  and  smelting,  a  total  of  $52.x  If  the 
price  of  spelter  were  5c.  per  Ib.  the  value  of  the  product  would  be  $48  and 
the  cost  $35-f-$10=$45.  If  the  price  were  4c.  per  Ib.  the  value  of  the 
product  would  be  $3840  and  the  cost  $28-f  $10=$38.  Consequently,  the 
smelter  who  had  made  a  profit  of  $5-60  per  ton  of  ore  when  spelter  was 
worth  6c.  would  make  only  40c.  with  spelter  at  4c.,  and  at  a  lower  price 
would  suffer  a  loss.  Such  a  schedule  to  determine  the  price  of  ore  is 
obviously  unscientific ;  after  a  few  months  of  trial  the  Missouri  and  Kansas 
Miners'  Association  was  compelled  to  abandon  it. 

The  formula,  V=700  P,  determined  only  the  value  of  ore  assaying  60% 
Zn.  For  ores  of  other  grades,  $1  per  ton  was  added  or  deducted  for 
each  unit  of  zinc  above  or  below  60,  but  when  the  tenor  in  zinc  fell  below 
53%  a  deduction  of  $1-50  was  made.  Iron  and  lead  were  each  penalized 
$1  per  unit  in  excess  of  1%,  up  to  4%  Fe  and  3%  Pb. 

VIII.  The  Paxton  schedule  of  1899  was  subsequently  modified  by  its 
author.     As  a  matter  of  interest,  the  revised  schedule  submitted  by  George 

1  These  figures  are  merely  illustrative  and  are  not  to  be  taken  as  representing  the  actual 
cost  of  smelting  or  recovery  of  metal  in  Missouri  and  Kansas. 


310  PRODUCTION    AND   PROPERTIES    OF   ZINC. 

B.  Paxton,  of  Joplin,  Mo.,  under  date  March  22,  1900,  is  herewith  pre- 
sented. This  schedule  was  intended  for  clean,  merchantable  blende,  free 
from  iron,  lead  or  excess  of  moisture.  According  to  Mr.  Paxton,  it  is  based 
on  the  actual  cost  of  smelting  the  various  grades  of  ore,  with  the  addition 
of  a  small  profit  to  the  smelter.  The  price  of  spelter  at  St.  Louis,  Mo.,  is 
assumed  as  the  basis. 

Lead  and  iron  in  the  ore  were  penalized  as  follows:  For  each  unit  of 
lead,  25  Ib.  were  to  be  deducted  from  the  weight  of  the  ore — i.e.,  if  2,000  Ib. 
of  ore  assaying  1%  Pb  were  offered  for  sale,  the  smelter  would  pay  for 
only  1,975  Ib.  according  to  the  above  schedule.  For  \%  Fe  45  Ib.  were 
deducted,  and  for  each  unit  in  excess  of  \%  55  Ib.  additional.  An  ore  as- 
saying 6%  Fe  would  therefore  be  taxed  320  Ib.  A  special  contract  was 
required  for  ore  assaying  more  than  6%  Fe. 

The  prices  established  by  this  schedule  are  considerably  below  those  which 
have  prevailed  in  the  Joplin  district  during  a  good  deal  of  the  time  since 
its  publication.  The  recent  practice  in  buying  ore  there  has  been  to  make 
a  certain  basis  price  for  the  grade  assaying  60%  Zn  and  pay  for  higher 
or  lower  grades  at  an  advance  or  deduction  of  $1  per  unit.  The  basis  price 
varies  according  to  the  price  of  spelter,  the  competition  among  the  smelters 
and  other  fluctuating  conditions. 

IX.  A  formula  used  in  1900  by  Kansas  and  Missouri  smelters  for  the 
purchase  of  Joplin  ore  was 

V=(16TXP)— S 
in  which 

V  =  value  of  ore  per  2,000  Ib. 

T  =  units  of  zinc  in  ore. 

P  =  value  of  zinc  per  pound  at  St.  Louis. 

8  =  returning  charge. 

The  returning  charge  included  cost  of  carting,  freight,  smelting  and  com- 
missions, lumped  at  $10-50,  and  the  smelter's  profit.  The  .latter  was  made 
equivalent  to  100  P  on  ore  assaying  60%  Zn  or  upward,  and  100  P+[10 
PX(60 — T)]  on  lower  grade  ore.  Consequently,  with  spelter  at  4c.  the 
smelter  would  reckon  a  profit  of  $4  per  ton  on  60%  ore  and  $4+  ($040X10) 
=$8  per  ton  on  50%  ore.1 

This  formula  is  substantially  the  same  as  Nos.  1,  2a,  3  and  6.  A  recov- 
ery of  80%  of  the  zinc  in  the  ore  is  reckoned  and  on  that  basis  the  assay 
in  units  multiplied  by  16  gives  the  number  of  pounds  of  zinc  to  be  paid  for. 
The  necessary  discount  from  the  St.  Louis  value  of  the  metal  is  included  in 
the  returning  charge.  The  greater  margin  demanded  by  the  smelter  in  the 

*W.  George  Waring,  Eng.  &  Min.  Journ.,  July  14.  1900. 


SAMPLING   AND   VALUATION    OF   ORES. 


311 


PAXTON   SCHEDULE   OF   ZINC   ORE    PRICES. 


Prioeof 
Spe'ter 
Mr  100 
Ibs. 

50% 

51% 

52% 

53% 

54% 

55% 

56% 

57% 

58% 

59% 

60% 

61% 

62% 

63% 

64% 

65% 

3-00 

7-50 

8-28 

9-06 

9-84 

10-62 

11-40 

12-18 

12-96 

13-74 

14-52 

15-30 

15-78 

16-26 

16-74 

17-22 

17-70 

3-05 

7'80 

8-59 

9'  38 

10-18 

10-97  11-76 

12-56 

13-35 

14-14 

14-94 

15-73 

16-21 

16-70  1  17-19 

17-68 

18*17 

3-10 

8-10 

8-90 

9-71 

10-51 

11.32 

12-12 

12-93 

13-73 

14-54 

15-35 

16-16 

16*65 

17-15  17'64 

18-14 

18'64 

3-15 

8'40 

9-21 

10-03 

10*85 

11.67 

12-49 

13-31 

14-13 

14-95 

15-77 

16-59 

17-09 

17*60  18'09 

18-60 

19-11 

3-20 

8-70 

9-53 

10-36 

11-19 

12-02 

12-86 

13-69 

14'52 

15-35 

16-18 

17-02 

17*53 

18*04  18'55 

19-06 

19-58 

3'25 

9-00 

9-84 

10-69 

11-53 

12-38 

13-28 

14-07 

14-91 

15-71 

16'60 

17-45 

17-97 

18-49  19*01 

19-53 

20-05 

3-30 

9-30 

10-15 

ll'Ol 

11-87 

12-73 

13'59 

14-44 

15-30 

16-13 

17-02 

]7'88 

18-40 

18-931  19-46 

19*99 

20-52 

3-35 

9-60 

10-47 

11-34 

12-21 

13-08 

13-95 

14'82 

15-69 

16-56 

17-43 

18'31 

18*84 

19-38 

19-91 

20-45 

20-99 

3'40 

9-90 

10-78 

11-67 

12-55 

\3'43 

14-32 

15-20 

16-09 

16-97 

17-86 

18-74 

19-28 

19*83 

20-37 

20-92 

21'41 

3-45 

10-20 

11-09 

11-99 

12-89 

13-79 

14-68  15-58 

16-48 

17-38 

18-28 

19-17 

19-72 

20-27 

20'82 

21-37 

21-93 

3'50 

10-50 

11-41 

12-32 

13-23 

14-14 

15'05  15'96 

16-87 

17-78 

18-69 

19-60 

20*16 

20-72 

21*28 

21-84 

22-40 

3-55 

10'80 

H'72 

12-64 

13'57 

14-49 

15-41 

16'33 

17-26 

18-18 

19-10 

20-03 

20-59 

21-16 

21-73 

22-30 

22-87 

3-60 

11-10 

12-03 

12-97 

13-91 

14-84 

15-78 

16-72 

17-65 

18-59 

19*53 

20*46 

21-03 

21-61 

22'18 

22-76 

23-34 

3-65 

11-40 

12-34 

13'  29 

14-24 

15-19 

16-14 

17-09 

18-04 

18-99 

19-94 

20-89 

21-47 

22-05 

22'64 

23-22 

23-81 

3-70 

11.70 

12'66 

13-62 

14-58 

15-54 

16-51 

17-47 

18-43 

19-39 

20-35 

21-32 

21-91 

22*50 

23'09 

23-68 

24-28 

3-75 

12-00 

12-97 

13*95 

14-92 

15-90 

16-87 

17-85 

18-82 

19-80 

20-77 

21-75 

22-35 

22-95 

23'55 

24-15 

24-75 

3-80 

12'30 

13-28 

14-27 

15'26 

16-25 

17-24 

18'22 

19-21 

20-20 

21-19 

22-18 

22-78 

23-39 

24-00 

24-61 

25-22 

3-85 

12-60 

13-60 

14-60 

15-60 

16-60 

17'60 

18-60 

19-60 

20-60 

21-60 

22-61 

23-22 

23-84 

24  "45 

25-07 

25'69 

3-90 

12*90 

13-91 

14'93 

15-94 

16-95 

17-97 

18-98 

20-00 

21-01 

22-02 

23-04 

23-66 

24-29 

24'91 

25-53 

26-16 

3-95 

13-20 

14-22 

15-25 

16-28 

17-30 

18-33 

19'36 

20-38 

21-41 

22-44 

23-47 

24-10 

24-73 

25'36 

25-99 

26-63 

4'00 

13-50 

14-54 

15'58 

16-62 

17-66 

18-70 

19-74 

20*78 

21-82 

22-86 

23-90 

24-54 

25-18 

25'82 

26'46 

27'10 

4-05 

13'80 

14'85 

15-90 

16'96 

18-01 

19-06 

20-11 

21*17 

22-22 

23-27 

24-33 

24-97 

25-62 

26'27 

26-92 

27-57 

4-10 

14-10 

15-16 

16-23 

17-30 

18*36 

19-43 

20-50 

21-56 

22-63 

23-70 

24-76 

25-41 

26-07 

26*72 

27'38 

28-04 

4-15 

14*40 

15-47 

16-55 

17'63 

18-71 

19-79 

20-87 

21-95 

23-03 

24-11 

25-19 

25-85 

26-51  27'18 

27-84 

28-51 

4-20 

14-70 

15*79 

16-88 

17-97 

19*06 

20'16 

21-25 

22-34 

23-43 

24-52 

25-62 

26-29 

26-96  !27'63 

28-30 

28'98 

4'25 

IS'OO 

16-10 

17'21 

18'31 

19-42 

20-52 

21*63 

22-73 

23-84 

24-94 

26'OS 

26-73 

27-41  J28'09 

28'77 

29-45 

4-30 

15-30 

16*41 

17-53 

18*65 

19-77 

20-89 

22-00 

23-12 

24-24 

25-36 

26-48 

27-16 

27-85 

28'54 

29-23 

29'92 

4'35 

15-60 

16-73 

17-86 

18-99 

20-12 

21-25 

22-38 

23-51 

24-64 

25-77 

26-91 

27-60 

28-30 

28'99 

29'69 

30'39 

4-40 

15'90 

17-04 

18-18 

19-33 

20-47 

21-61 

22'75 

23-90 

25-04 

26-19 

27-34 

28-04 

28-75 

29  '45 

30-15 

30-86 

4-45 

16*20 

17-35 

18'51 

19-67 

20-83 

21-99 

23-14 

24-30 

25-46 

26-62 

27-77 

28-48 

29-19 

29'90 

30-61 

31-33 

4-50 

16'50 

17-67 

18*84 

20-01 

21-18 

22-35 

23-52 

24-69 

25-86 

27-03 

28-20 

28-92 

29-64 

30'36 

31-08 

31-80 

4-55 

16-80 

17-98 

19-16 

20-35 

21-53 

22-71 

23-90 

25'OS 

26-26 

27-44 

28-63 

29-35 

30-08 

30'81 

31-54 

32-27 

4'60 

17-10 

18-29 

19-49 

20-68 

21-88 

23-07 

24-26 

25-45 

26-64 

27-36 

29-06 

29-79 

30-53 

31'26 

32'OG 

32-74 

4-65 

17'40 

18-60 

19-81 

21-02 

22-23 

23-44 

24-65 

25-86 

27-07 

28*28 

29-49 

30-23 

30-98 

31*72 

32-47 

33-21 

4'70 

17-70 

18-92 

20*14 

21-36 

22-58 

23-81 

25-03 

26-25 

27-47 

28-69 

29'92 

30-67 

31-42 

32*17 

32-92 

33-68 

4'75 

IS'OO 

19-23 

20-47 

21-70 

22-94 

24-17 

25-41 

26'64 

27-88 

29-11 

30-35 

31-11 

31-87 

32*63 

33-39 

34-15 

4'80 

18-30 

19-54 

20*79 

22-04 

23-29 

24-54 

25-78 

27-03 

28-28 

29-53 

30-78 

31-54 

32-31 

33'08 

33-85 

34-62 

4'85 

18'60 

19'86 

21-12 

22*38 

23-64 

24-90 

26-16 

27-42 

28-68 

29*94 

31*21 

31-98 

32-76 

33'53 

34-31 

35-09 

4-90 

18-90 

20-17 

21-45 

22-72 

24-00 

25-27 

26-54 

27-82 

29-09 

30-36 

31-64 

32-42 

33-21 

33-99 

34'78 

35-56 

4'95 

19-20 

20-48 

21-77 

23-05 

24-34 

25-63 

26-91 

28'20 

29-49 

30-78 

32-07 

32-86 

33-65 

34-44 

35-23 

36-03 

5-00 

19'50 

20'80 

22-10 

23-40 

24-70 

26-00 

27-30 

28-60 

29-90 

31-20 

32-50 

33-30 

34-10 

34  '90 

35-79 

36'60 

5'05 

19-80 

21-11 

22-42 

23-74 

25-05 

26-36 

27-68 

28-99 

30-30 

31-62 

32-93 

33-73 

34-54 

35-35 

36-16 

36-97 

5-10 

20-10 

21-42 

22-75 

24-07 

25-40 

26-72 

28-05 

29-37 

30-70 

32-03 

33-36 

34-17 

34-99 

35'80 

36-62 

37-44 

5*15 

20-40 

21-73 

23-07 

24-41 

25-75 

27-09 

28-43 

29-77 

31-11 

32-45 

33-79 

34-61 

35-44 

36-26 

37*09 

37-91 

5-20 

20'70 

22-05 

23-40 

24-75 

26-10 

27-46 

28-81 

30-16 

31-57 

32-86 

34-22 

35-05 

35-88 

36'71 

37-54 

38'38 

5-25 

21-00 

22*36 

23-73 

25-09 

26-46 

27-82 

29-19 

30-55 

31-92 

33-28 

34-65 

35-49 

36-33 

37'17 

38-01 

38-85 

5'30 

21-30 

22-67 

24-05 

25-43 

26-81 

28-19 

29-56 

30-94 

32-32 

33-70 

35-08 

35-92 

36-77 

37-62 

38-47 

39-32 

5-35 

21'60 

22-99 

24-38 

25-77 

27-16 

28-55 

29-94 

31-33 

32-72 

34-11 

35-51 

36-36 

37-22 

38'07 

38-93 

39-79 

5'40 

21-90 

23*30 

24-71 

26-11 

27-51 

28-92 

30-32 

31-73 

33-13 

34-53 

35-94 

36-80 

37-67 

38-53 

39-40 

40-26 

5-45 

22-20 

23'61 

25-03 

26'44 

27-86 

29-28 

30-69 

32-11 

33-53 

34-95 

36-37 

37-24 

38-11 

38'98 

39-85 

40-73 

5'50 

22-50 

23-83 

25-36 

26-49 

28-22 

29-15 

31-08 

32-50 

33-14 

35-37 

36*80 

37-68 

38-56 

39-44 

40-32 

41-20 

5-55 

22'80 

24-24 

25'68 

27*13 

28'57 

30-01 

31-46 

32-90 

34-34 

35-79 

37-23 

38-11 

39-00 

39-89 

40-78 

41-67 

5-60 

23-10 

24-55 

26-01 

27-46 

28-92 

30-38 

31-33 

33-29 

34-74 

36-20 

37-66 

38-55 

39-45 

40*34 

41-24 

42-14 

'  5'65 

23-40 

24-86 

26'33 

27'80 

29-27 

30-74 

32-21 

33-68 

35-15 

36-62 

38-09 

38-99 

39-90 

40-80 

4171 

42-61 

5-70 

23'70 

25-18 

26-66 

28-14 

29'62 

31-11 

32-59 

34-07 

35-55 

37-03 

38-52 

39-43 

40-34 

41-25 

42-16 

43-09 

5'75 

24-00 

25-49 

26'99 

28-48 

29*98 

31-47 

32-97 

34-46 

35-96 

37-45 

38'95 

39-87 

40-79 

41'71 

42-63 

43-55 

5-80 

24-30 

25'80 

27'31 

28*82 

30-33 

31-84 

33-34 

34-85 

36-36 

37-87 

39-38 

40-30 

41-23 

42-16 

43-09 

44-02 

5-85 

24-60 

26-12 

27-64 

29-16 

30-68 

32-20 

33-72 

35-24 

36-76 

38-28 

39'81 

40-74 

41-68 

42'61 

43'55 

44-49 

5-90 

24-90 

26-43 

27'97 

29'50 

31-03 

32-57 

34-10 

35-64 

37-17 

38-70 

40-24 

41-18 

42-13 

43-07 

44-02 

44-96 

5'95 

25-20 

26-74 

28-29 

29-83 

31-38 

32-93 

34-47 

36-02 

37-57 

39-12 

40-67 

41-62 

42-57 

43'52 

44-47 

45*43 

6-00 

25-50 

27-06 

28'62 

30-18 

31-74 

33-30 

34-86 

36-42 

37-98 

39-54 

41-10 

42-06 

43-02 

43-98 

44-94 

45-90 

6'05 

25'80 

27-37 

28-94 

30-52 

32-09 

33-66 

35-24 

36*81 

38-38 

39-96 

41-53 

42-49 

43-46 

44-43 

45-40 

46'37 

6'10 

26-10 

27-68 

29'27 

SO'85 

32-44 

34-02 

35-61 

37-19 

38-78 

40-37 

41-96 

42-93 

43-91 

44-88 

45-86 

46-84 

6-15 

26-40 

27'99 

29-59 

31-19 

32-79 

34-39 

35-99 

37-59 

39-19 

40-79 

42-39 

43-37 

44-36 

45-34 

46'33 

47-31 

6'20 

26-70 

28-31 

29-92 

31*53 

33-14 

34-76 

36-37 

37-98 

39-59 

41-20 

42*82 

43-81 

44-80 

45-79 

46-78 

47-78 

6-25 

27-00 

28-62 

30-25 

31-87 

33'SO 

35-12 

36-75 

38-37 

40-00 

41-62 

43-25 

44-25 

45-25 

46-25 

47-25 

48-25 

6'30 

27-30 

28-93 

30-57 

32-21 

33-85 

35-49 

37-12 

38-76 

40-40 

42-04 

43-68 

44-68 

45-69 

46'70 

47-71 

48-72 

6'35 

27-60 

29-25 

30-90 

32-55 

34-20 

35-85 

37-50 

39-15 

40-80 

42-45 

44-11 

45-12 

46-14 

47-15 

48*17 

49-19 

6-40 

27-90 

29*56 

31-23 

32-89 

34-56 

36-22 

37-88 

39-55 

41-22 

42-88 

44-54 

45-56 

46-59 

47-61 

48-64 

49'66 

6'45 

28-20 

29-87 

31-55 

33-22 

34-90 

36-58 

38-25 

39-93 

41-61 

43-29 

44-97 

46*00 

47-03 

48-06 

49-09 

50-13 

6'50 

28-50 

30-19 

31-88 

33-57 

35-26 

36-95 

38-64 

40'33|42-02  43'71 

45-40 

46-44 

47-48 

48-52 

49-56 

50-60 

312 


PRODUCTION    AND    PROPERTIES    OF    ZINC. 


PAXTON    SCHEDULE  OF  ZINC   ORE   PRICES     (Continued). 


t*i.ut)  0. 

goiter 
ser  100 
'  )bs. 

53% 

51% 

52% 

53% 

54% 

55% 

56% 

57% 

58% 

59% 

6J% 

61% 

62% 

61% 

64% 

65% 

6'55 
6-60 
6-65 
6-70 
6-75 
6-80 
6-85 
6-90 
6-95 
7-00 

28-80 
29-10 
29-40 
29-70 
30*00 
30-30 
30-60 
30-90 
31-20 
31.50 

30-50 
30-81 
31-12 
31-44 
31-75 
32-06 
32-38 
32-69 
33-00 
33-32 

32-20 
32-53 
32-85 
33-18 
33-51 
33-83 
34-16 
34-49 
34-81 
35-14 

33-91 
34-24 
34-58 
34-92 
35-26 
35-60 
35-94 
36-28 
36-61 
36.96 

35-61 
35-96 
36-31 
36-66 
37-02 
37-37 
37-72 
38'OS 
38-42 
38-78 

37-31 
37-67 
38-04 
38'41 
38-77 
39-14 
39-50 
39'87 
40-23 
40'60 

39-02 
39-39 
39-77 
40-15 
40-53 
40-90 
41-28 
41-66 
42-03 
42-42 

40-72 
41-10 
41-50 
41-89 
42-28 
42-67 
43-06 
43-46 
43-84 
44-24 

42-42 
42-82 
43-23 
43-63 
44-04 
44-44 
44*84 
45-25 
46-65 
46  06 

44-13 
44-54 
44-96 
45-37 
45-79 
46-21 
46-62 
47-05 
47-46 
47-88 

45-83 
46-26 
46-69 
47-12 
47-55 
47-98 
48-41 
48-84 
49-27 
49-70 

46-87 
47-31 
47-75 
48-19 
48-63 
49'06 
49-50 
49-94 
SO'38 
50-82 

47-92 
48-37 
48-82 
49-26 
49-71 
50-15 
50-60 
51-05 
51-49 
51-94 

48-97 
49'42 
49-88 
SO'33 
50-79 
51-24 
51-69 
52-15 
52-60 
53-06 

50-02 
50-48 
50-95 
51-40 
51-87 
52-33 
52-79 
53-26 
53-71 
54-18 

51-07 
51-54 
52-01 
52-48 
52-95 
53-42 
53-89 
54-36 
54-83 
55-30 

case  of  the  low  grade  ore  compensates  for  the  increased  cost  of  treatment 
and  lower  recovery  of  metal  from  it. 

VALUE  OF  LEAD  AND  SILVER  BEARING  ZINC  ORES. — In  general  the  pres- 
ence of  lead  in  a  zinc  ore  detracts  from  its  value,  since  the  cost  of  smelting 
is  likely  to  be  increased  by  the  more  rapid  destruction  of  retorts  (and  con- 
sequent greater  loss  of  zinc),  while  the  quality  of  the  spelter  produced  is 
deteriorated  by  the  lead  which  distils  over  with  the  zinc,  and  its  value  per 
pound  is  lessened  to  an  extent  which  is  not  offset  by  the  increase  in  the 
weight  of  metal  produced.  For  those  reasons  a  penalty  is  frequently  im- 
posed on  lead  in  ore  when  it  exceeds  a  stipulated  limit,  which  in  Kansas  is 
sometimes  fixed  at  1%,  the  penalty  being  generally  50c.@$l  per  unit  for 
lead  in  excess  of  that  amount.  A  penalty  of  $1  per  unit  is  much  too  high, 
the  extra  cost  entailed  upon  the  smelter  by  a  lead  content  in  the  ore  being 
ordinarily  a  good  deal  less  than  that.  Frequently  lead  is  not  taxed  at  all. 
The  smelters  of  Belgium  distil  regularly  mixtures  of  ore  which  are  rather 
high  in  lead  and  recover  a  portion  of  that  metal  by  jigging  the  residues 
drawn  from  the  retorts  and  smelting  the  concentrate,  whereby  silver  is  re- 
covered together  with  the  lead.  In  the  purchase  of  such  ores  the  smelter 
of  course  reckons  upon  the  value  of  the  lead  and  silver  recoverable,  minus 
the  additional  cost  of  the  process,  and  makes  his  price  accordingly. 

DEDUCTION  IN  VALUE  ON  ACCOUNT  OF  IRON. — Western  smelters  generally 
deduct  $1  per  unit  (sometimes  only  50c.)  of  iron  in  excess  of  a  certain  limit, 
which  is  fixed  variously  at  \%  or  2%.  In  the  Joplin  district  an  ore  con- 
taining 6%  Fe  and  upward  is  marketed  with  more  or  less  difficulty,  the 
smelters  generally  preferring  the  ores  of  higher  grade  and  purity.  In 
Europe,  where  no  ore  so  clean  as  that  of  Joplin  is  available,  mixtures  con- 
taining 5%  to  10%  Fe-j-Mn  are  habitually  smelted.  Manganese  plays  the 
same  part  in  zinc  smelting  that  iron  does,  and  the  units  of  manganese  shown 
by  assay  are  added  to  the  units  of  iron  in  computing  the  value  of  an  ore. 


SAMPLING   AND   VALUATION    OF   ORES.  313 

CONCLUSION. — Besides  the  contents  of  the  ore  in  zinc,  lead,  silver,  iron, 
manganese  and  other  valuable  or  deleterious  elements,  numerous  other  fac- 
tors enter  into  consideration  in  determining  its  value.  The  smelter  aims  for 
various  metallurgical  reasons  to  treat  a  product  of  a  certain  uniform  com- 
position, which  must  generally  be  prepared  by  making  a  mixture  of  various 
ores.  Competition  may  necessitate  that  he  has  to  pay  a  comparatively  high 
price  for  the  scarce,  high  grade  material,  wherefore  he  will  scheme  to  recoup 
himself  by  buying  the  more  plentiful,  inferior  ores  at  a  relatively  low  price. 
The  average  cost  at  which  he  is  able  to  secure  his  desired  mixture  will  form 
the  basis  of  his  calculations. 

The  actual  cost  of  smelting  is  determined  by  the  experience  in  treating 
the  mixtures  which  are  regularly  distilled.  It  varies  naturally  from  time 
to  time  according  to  the  wages  for  labor,  cost  of  coal,  and  other  conditions. 
In  the  cost  of  smelting,  all  such  general  charges  as  taxes,  insurance,  and  the 
expense  of  administering  the  business  must  be  included.  Furthermore, 
there  must  be  an  allowance  for  amortization  of  the  cost  of  the  works,  which 
will  not  last  indefinitely  without  replacement  of  their  parts  at  various  inter- 
vals. The  smelter  expects  to  realize  a  profit  over  and  above  the  cost  of  the 
ore  and  the  expense  of  smelting  it,  including  all  charges,  which  will  be  a 
fair  return  upon  the  money  invested  in  the  business,  and  he  looks  for  a 
return  which  will  be  sufficiently  large  to  reimburse  him  for  the  numerous 
risks  that  must  be  taken  in  this,  as  in  any  other  manufacturing  enterprise. 


INDEX. 


PAGE 

Aachen,  manufacture  of  brass  at 3 

Acid   (see  Sulphurous,  Sulphuric,  etc.). 

Acid  sulphate  of  zinc 137 

Acids,  action  on  zinc 137 

Advantages  of  ore  sorting 241 

Africa,  zinc  ore  deposits  of 207,  228 

Agricola   mentions   zinc 2 

Aich's    metal 146 

Ain  Arko  mines,  Algeria 228 

Aktiengesellschaft   Berzelius,   Germany.  19 
Aktiengesellschaft     fur     Bergbau     und 
Zinkhiittenbetrieb  zu  Stolberg   und    in 

Westphalen 19 

Aktiengesellschaft   fur   Zink    Industrie, 

Vormals  W.   Grillo 19 

Alexander,   H.   II.,   method   of  lead  as- 
saying      112 

Algeria,  production  of  zinc  ore 64 

Zinc  deposits  of 228 

Algerian  zinc  ore,  composition  of 29 

Aliva   mines.    Spain 226 

Alkalies,  action  on  zinc 137 

Alloys,  determination  of  zinc  in 125 

Alloys  of  zinc 141 

Almeria,  production  of  zinc  ore 37 

Altenberg   (see  also  Vieille  Montague). 

Zinc  mines   of 209 

Altgliick.  Germany,  zinc  mines 214 

Alumina te  of  zinc 163 

Aluminum,  as  impurity  in  spelter 140 

Aluminum-zinc  alloys    142 

Amalgams   of  zinc 145 

American  Metal  Co 63,  73,  74 

American  sheet  zinc  gauge 51 

American  Smelting  &  Refining  Co 47 

American  zinc  smelters,  list  of 20 

Ammeberg,  Sweden,  ore  dressing 256 

Zinc  mines    -08.  227 

Ammoniacal  chlorides  of  zinc 165 

Ampsin,  Belgium,  smelting  works  at.  .  .  6 
Analyses   (see  also  Assays). 

of  European  zinc  ores 29 

of  Silesian  calamine 218 

Analysis,  methods  of 93 

of  spelter    120 

of  Virginia  coal 38 

Andosa  mines.    Spain 226 

Andrew's    method    of    determining   sul- 
phur   124 

Angleur,   Belgium,  zinc  smeltery  at.. 6. 

Angouleme.  deposits  of  zinc  ore  near.  .    210 

Antheit.    Belgium,   smeltery   at 6.     17 

Anthony,    Wm.,    on    Wetherill    separa- 
tors     27.") 

Anthracite,   calorific  power  of 42 

Anthracite  coal  in  Pennsylvania 41 

Antifriction  metal    146 

Antimony  as  impurity  in  spelter 140 

Antimony-zinc  alloys    143 

Antonienhiitte.    Silesia,   smelting  works 

18 


Apparatus  for  determining  sulphurous 

acid    " 131 

Argall,  Philip,  on  ore  crushing 242 

on  ore  sampling 293 

Argentan    14$ 

Aristotle  mentions  Mossinoecian  copper  1 
Arkansas,  magnetic  separation   of  zinc 

ore  in   288 

Zinc  deposits  of 178,  179 

Arnao,  Spain,  zinc  works  at.... 20,  37,  226 

Arsenic  as  impurity  in  spelter 140 

in  Silesian   zinc  ore 217 

in  spelter,  determination  of 126 

Assay  methods  for  cadmium Ill 

for  iron 115 

for  lead 112 

for  lime   118 

for  magnesia    120 

for   sulphur 121 

Assay  of  zinc  dust 128 

Zinc  in  alloys 125 

Assays  of  (see  also  Composition  of) 

Arkansas  zinc  ore ,. .  .  180 

Broken  Hill  zinc  ore 229,  230,  284 

Canadian  zinc  ore 205 

Colorado  zinc  ore 181,  182 

French  zinc  ore 210 

German  zinc  ore 214 

Grecian  zinc  ore 222 

.Toplin  zinc  and  lead  ore 188,  189 

Mexican   zinc   ore 206 

New  Jersey  zinc  ore 193,  267,  278 

New  Mexico  zinc  ore 194 

Pennsylvania   zinc  ore 197 

Rammelsberg   ore    213 

Sardinian   zinc  ore 223,  224 

Silesian  zinc  ore 10,   217,  218 

Swedish  zinc  ore 227 

Tasmanian   zinc  ore 231 

Tennessee  zinc  ore 198,  199 

Ftah  zinc  ore 200 

Virginia   zinc  ore 201 

Assaying,   methods  of    (see  also  Deter- 
mination  and  Assay  Methods) 93 

Asturienne.  Compagnie  Royale.  .18,  20, 

30,  37,  226,  228 

Atlantic   Cable  mine.   Rico,   Colo 182 

Atmospheric  action   on   zinc 137 

Atomic  weights    133 

Auby.  France,  zinc  works  at.  .  .  .18,   30,  226 

Aufsrliluss   mine.    Silesia 219 

Aurichalcite    175 

Aurichalcum     1 

Aurora.  Mo.,  zinc  mines 183,  187.  18S 

Austen    (see  Roberts- Austen). 

Austinville.  Va..  magnetic  separation  at  270 

Zinc  mines    200 

Australia,  magnetic  separation  in 284 

Occurrence  of  native  zinc  in 177 

Production  of  zinc  ore  in 64.  69 

Zinc  ore  deposits  of 207.  229 

Australian  zinc  ore,  composition  of.  ...  29 

Austria,  consumption  of  zinc 77.  80 

Production  of  zinc  ore 64 


INDEX. 


PAGE 

Production  of  spelter 71,  72 

Zinc  ore  deposits  of 208 

Zinc  smelters  of 17 

Austrian  zinc  ore,  composition  of 29 

Austro-Belge,  Soc.  Anon 17 


Babbitt  metal    146 

Baden,  zinc  deposits  of 212 

Baelen-Wezel     blende     roasting     plant, 

Belgium    17,     25 

Baerenhof-Bykowine,    Silesia,     smelting 

works    ; 18 

Bag  apparatus  for  fume  collection,  in- 
vention of   13 

Ball  mills   242 

Ballard,    E.    G 108 

Barium 133 

Barium    chloride,    precipitation    of  sul- 
phur with    122 

Bartlett  table 181,  243,  250 

Barus,  C.,  on  boiling  point  of  zinc.  .  .  .    134 

Barytes,  used  in  pigments 48 

Basic  carbonates  of  zinc 160 

Chlorides    of   zinc 164 

Sulphates,  assay  of 130 

Sulphates  of  zinc 155 

Becquerel,  on  boiling  point  of  zinc.  . .  .    134 
on  electrical  conductivity  of  zinc.  .   136 
Behrens,  H.,  on  microscopical  examina- 
tion  of  metals 139 

Beilby,  G.  T 57 

Belgian  method   of  smelting 22,  232 

Ore,   composition   of 29 

Sheet   zinc   gauge 51 

Belgium,  coal  resources  of 25 

Consumption  of  zinc 77,     80 

Cost  of  coal 27,     28 

Fire  clay   28 

Grade  of  ore  smelted 30 

History  of  zinc  smelting 4,       5 

Imports  of  zinc  ore  from  Spain ....    226 

from   Turkey    227 

Map  of 26 

Production  of  zinc  ore 64,  66,     88 

Production  of  sheet  zinc 90 

Production  of  spelter 16,  71,     72 

Rate  of  wages  in 28 

Valuation  of  zinc  ore  in 305 

Zinc  ore  deposits 208,  209 

Zinc  industry  in 25 

Zinc  smelters  of 17 

Belleville  coal   district    Illinois 41 

Belleville,  Mo.,  zinc  mines 190 

Bellom,  M.,  on  ore  dressing  in  Germany  214 

Belts  for  ore  sorting 240 

Bendzin,  Russia,  zinc  works ....  20,  36,   226 

Bensberg  mines,   Germany 32,  214 

Bensdorff,  on  zinc  carbonates 162 

Bergamo,  Italy,  zinc  mines  of 225 

Berge-Borbeck.  Germany,  zinc  works  19,     32 

Bergenpoint,  N.  J.,  zinc  works  at 14 

Bergenpoint  Zinc  Co. 21,  196 

Bergisch-Gladbach,     Germany,    zinc 

works 19 

Bergwerksgesellschaft    G.    V.    Giesche's 
Erben   (see  Giesche's  Erben). 

Beringer,  C.  &  ,T.  J 117,  127 

Berlin  argentan   146 

Bernhardihiitte.  Silesia   18,  24,     91 

Bertha  mines,  Va.,  description  of 201 

Bertha  Zinc  &  Mineral  Co 20.  38, 

198,  200,   202 

Berthelot,  D.,  on  boiling  point  of  zinc.    134 

Berthier,  on  properties  of  zinc  oxide.  .   158 

OB     properties     of     zinc     sulphide, 

149,  150,  151 


Beryllium    133,  159 

Bethlehem,      Penn.,      smelting     works, 

14,  20,  195 

Beudant,  on  nomenclature  of  zinc  ores  170 
Beuthen,     Germany,     manufacture     of 

brass  at 7 

Zinc  mines 3,   7,  215 

Beuthenerhiitte,    Silesia 18,  91 

Biache     St.     Waast,     Soc.     Anon,     des 

fonderies  de   17    t 

Biddery  ware   147 

Bingham  Canon,   Utah,  zinc  ore 200 

Binon  and  Grandfils 6 

Bismuth-zinc   alloys    143 

Bisulphite  of  zinc 152 

Blackmore,  William    34 

Blake,   W.   P 250 

on  New  Mexico  zinc  deposits 194 

Blake   crushers    242 

Blake   roasting  furnace 256 

Blende,  analyses  of  Silesian 219 

Assay  of   94 

Blende,  character  of  Arkansan 180 

of  Pennsylvanian    197 

Saxon    233 

Silesian    217 

Wisconsin    204 

Determination  of  iron  in 117 

Ferruginous,   magnetic   permeability 

of    269 

in  Greece   222 

Mineralogical  properties   171 

Occurrence  at  Ammeberg 227 

Production  in  Belgium 66 

Silesia    - 67 

Separation  from  marcasite 256 

from   pyrites    255 

from  siderite    262 

Shipments  from  Cartagena,  Spain..  226 

Blende  roasting 148,   154,  157 

Bleiberg,  Austria,  zinc  mines 175,  208 

Bleyberg,  Belgium,  smelting  works  at.  17 

Zinc  mines    209 

Bloemeke,  C.,   on  magnetic  separators.  267 
Blue  powder  (see  Zinc  Dust). 

Bobrek,  Silesia,  smelting  works 18 

Bobrekhiitte,  Silesia    10 

Bogutschiitz,   Silesia,  smeltery  at 18 

Boiler  corrosion,  zinc  as  preventive  for  55 

Boiling  point  of  zinc 134 

Boleslaw  mines.   Poland 225 

Bolley,  on  specific  gravity  of  zinc 134 

Boom,  Soc.  Anon,  metallurgique  de....  17 

Boom,  Belgium,  smelting  works  at.  ...6,  17 

Bonne  Terre,  Mo.,  ore  dressing  practice  251 

Borbeck,  Germany,  zinc  works 19 

Borgnet,  George   7 

Bormettes  zinc  mines.  France 212 

Bosnia,  production  of  zinc  ore 65 

Bottone's  scale  of  hardness 136 

Boussingault,  on  zinc  carbonates 161 

Boyle,  on  zinc 2 

Branner,  J.  C..  on  Arkansas  zinc  mines  180 

Brass,  composition  and  properties.  144,  146 
Brass-making,  consumption  of  zinc  for, 

49,  58 

by  cementation  process 

in  Connecticut   47 

Brass  manufacture,  character  of  spelter 

required    139 

in  Silesia   J 

Brass  rolling    HP 

Brass  works,  early  establishment  of .  . . 

Breakers    242 

Breaking  ore   234 

Hammers  for   236 

Breslau  as  a  spelter  market S2 

Price  of  zinc  at 1 3.  84.  86  . 


316 


INDEX. 


PAGE 

Brick    (see  Fire  Brick). 

Bridgman  sampler   298 

Brilon,   Westphalia,   zinc  mines 220 

Brisson,  on  specific  gravity  of  zinc.  . .  .    134 

Bristol,  England,  zinc  works 3,     19 

Brittany,  zinc  ore  deposits  of 210 

Broken  Hill.,  N.  S.  W.,  magnetic  sepa- 
ration at   259,  284 

Ore   deposits   of 213,  229 

Zinc   ore 233 

Bromides  of  zinc 166 

Brongniart,    on    nomenclature    of    zinc 

ores 170 

Bronze,  composition  of 146,  147 

White    58 

Brooke  and  Miller. 170 

Bruce,  Kan.,  smelting  works  at .      21 

Brunner,  Mond  &  Co 19 

Brunton  sampler 298 

Buddies    243 

Budel,  Holland,  smelting  works 20 

Buescher,  on  basic  zinc  sulphate 155 

Buettgenbach,  F.,  process  of  ore  dress- 
ing        258 

Buratite    175 

Burned  zinc   141 

Butter  of  zinc 163 

Bykowine.    Silesia,   smelting  works....      18 


Cadmiferous  blende   172 

Smithsonite    174 

Cadmium,  as  impurity  in  zinc 140 

Assay  for Ill 

Atomic  weight   133 

in  Joplin  zinc  ore 188,  189 

in  spelter,  determination  of 127 

in  zinc  ore  from  Weisloch 212 

Occurrence  in  zinc  ore 172,  174 

Tenor  of  Silesian  ore 233 

Caitas,  Sardinia,  zinc  mines 223 

Calamine 176 

Analyses   of   Silesian 218 

Calcination   of 35,  159 

Character  of  Silesian 217 

Concentration  of   233 

in  Greece   222 

in  Missouri    187,  188 

Origin  of  name. . . 170 

Production  in  Belgium 66 

in  Silesia   67 

Reducibility  of 158 

Shipments  from  Cartagena,  Spain.  .   226 

TTsed  for  brass-making 1,  2,       3 

Value  of  Missouri 304 

Calcining  furnace 263,   264,  265 

Calcination  of  calamine 35,  159 

Calvert,   on  expansion  of  zinc 136 

on  thermal  conductivity  of  zinc.  . . .    136 

Calcium    133 

Calorific  power  of  American  coals 42 

Cameros,  zinc  found  in  ruins  of 1 

Cammett  table    181,  243 

Campine,  Societe  de  la 20 

Canada,  zinc  ore  deposits 205 

Carbon  as  impurity  in  spelter 141 

Carbonates  of  zinc 160,  173 

Cardiganshire,  zinc  deposits   of 221 

Carinthia,  history  of  zinc  smelting  in  4,       6 

Zinc  deposits  of 175,  208 

Carinthian  method  of  smelting 23 

Carlshutte,  Silesia   18,     91 

Carondelet  zinc  works,  Missouri 15 

Carpenter,  R.   Forbes 35 

Cartagena,  Spain,  zinc  mines  near  208,  226 

Carterville.   Mo.,   zinc  mines 183 

Case.  W.  II..  on  zinc  mining  in  Virginia   202 


Cassiterite,  occurrence  with  blende. .    .    138 

Castings  of  zinc 53 

Caucasus,  zinc  deposits  of 225 

Central  Metal  and   Smelting  Co. . .  .  19 

Central  mine,  Broken  Hill 230 

Chamotte   (see  Fire  Clay). 

Champion,  John    3,       7 

Chemical   properties  of  zinc 137 

Chenhall,  method  of  zinc  smelting.  ...  6 

Cherokee,  Kan.,  smelting  works  at.  ...  21 

Cherokee-Lanyon   Spelter   Co 21,     22 

Cherokee   Smelting  Co 21 

Cherokee  Smelting  and  Refining  Co 22 

Cherokee  Zinc  Co 

Cherry  vale,    Kan.,    smelting   works    at, 

21,     38 

Chinese  origin  of  zinc  smelting 3 

Chlorine,  action  on  zinc  oxide 159 

Action   on  zinc  sulphide 151 

as  impurity  in  spelter 141 

Chloride  of  zinc 61,  159,  163 

Chromate  of  zinc 162 

Chropaczow,    Silesia,   smeltery  at 18 

Cilli,  Austria,  zinc  works  at 17 

Cinder  for  reduction  material 11 

Clairac,   France,  zinc  mines 211 

Clarahiitte,   Silesia 9,   18,  91 

Clark  mine,  Va 202 

Clarke,  F.  W.,   on  atomic  weights 133 

Clausthal,   Germany,   zinc   mines 212 

Ore  sorting  at 238 

Clay  (see  also  Fire  Clay). 

Zinkiferous   176,   188,  201 

Clerc,  F.  L 39,   195,  197 

on  New  Jersey  zinc  deposits.  .  .192,  193 

Cleveland,    W.    P 286 

Cleveland-Knowles    magnetic    separator  285 

Clinton,  Tenn.,  smelting  works  at... 21,  200 

Coal,  anthracite  field  of  Pennsylvania.  41 

Character   of  Illinois 41 

Kansas    42,  184 

Classification  of  Belgian 27 

Composition  of  Virginian 38 

Consumption  by  Belgian  smelters. .  28 

for  sheet  zinc  rolling 28 

in  smelting  in  Silesia 8,  11 

Cost  at  Joplin,   Mo 248 

in  Belgium    27,  28 

in  France   30 

in  Illinois   42 

in  Kansas   42 

in  Silesia   11,  33 

in  Tasmania    231 

in  Wales   34 

in  Westphalia   31 

Resources   of   Belgium 25 

Rhenish  Prussia   31 

Russia    36 

United  States   41 

Westphalia   31 

Cockerill,   A.   B 21,  22 

Cockle  Creek  smeltery,  N.  S.  W 230 

Coefficient  of  expansion  of  zinc 136 

Coke,  cost  in  Tasmania 231 

Collinsville,  111.,  smelting  works  at. 38,  41 

Collinsville  Zinc  Co 21 

Col.   Sellers  mine,  Leadville,  Colo 181 

Cologne,  average  price  of  spelter  at.  .  .  84 

Colorado,  production  of  zinc  ore 70 

Zinc  deposits  of 45,  178,  181 

Colorado  Zinc  Co 181,  278 

Columbia  mine,   Ky 182 

Combinations     to     regulate     price     of 

spelter 88,  89 

Compagnie    Franchise     des     Mines     du 

Laurium    222 

Cornpagnie  Royale  Asturienne  des  Mines 
(see  Asturienne). 


INDEX. 


317 


PAGE 

Composition  of  European  zinc  ore 29 

New  Jersey  zinc  ore 193 

Silesian  zinc  ore 218 

Spelter    140 

Tennessee  zinc  ore 198 

Concentration  by  gravity 241 

Concentration  of  Broken  Hill  ore 230 

Concentrating  mills   245,  246 

Arrangement  of 244 

Constant  sampler   298 

Conductivity  of  zinc 136 

Consumption  of  zinc,  channels  of 49 

in  brass-making 58 

in  cyanide  process 57 

in  the  United   States 46 

Statistics  of 75,  77,  78,  79.     80 

Convers,    G.    G.,    process    of    magnetic- 
separation    207 

Cooley  jig 246 

Copper  as  impurity  in  spelter 140 

in  spelter,  determination  of 127 

Copper-zinc  alloys    144 

Cordelia,  Andre   221,  222 

Cordoba,  production  of  zinc  ore 37 

Cornwall,   zinc  mines   of 220 

Corphalie,  Belgium,  smeltery  at 6,     17 

Zinc  mines   at 210 

Cost  of  calcining  calamine 35 

Coal  at  Joplin,  Mo 248 

in  Belgium   27,     28 

in  France   30 

in  Illinois   42 

in  Kansas 42 

in  Rheinland  and  Westphalia. .  .      31 

in  Silesia   33 

in  Wales   34 

Developing  mines  at  Joplin.  Mo.  . .  .    253 

Fire  brick  in  the  United  States 46 

Fire  clay  in  Belgium 28 

in  Germany    31 

in   Silesia    33 

in  the  United  States 46 

in  Wales   34 

Labor  in  Silesia 11 

in  the  United  States 46 

Magnetic   separation    at   Lohmanns- 

feld 283 

in  New  Jersey 278 

Milling  at  Broken  Hill 230 

in  Joplin  district 248 

Mills  in  Joplin  district 248 

Mining  at  Broken  Hill 230 

at  Joplin,   Mo 252 

in  Greece   35 

in  Tasmania 231 

Natural  gas 44,     45 

Ore  crushing   235 

Ore  dressing  in  Germany 214 

Ore  sampling 300 

Ore  sorting   240 

Producing  spelter  in  Silesia 9 

Producing  zinc  ore  at  Joplin.  Mo.  .    252 

Roofing    54 

Shaft  sinking  at  Joplin,  Mo 190 

Smelting    290 

Spalling  ore   235 

Vezin  sampler    299 

Crafts,  on  boiling  point  of  zinc 134 

Crawford,   inventor  of  galvanizing.  ...      48 

Creede,  Colo.,  zinc  ore 70,  182 

Crith,  definition  of 135 

Cronstedt  and  Rinmann 4 

Crushers    242 

Crushing  of  ore 235,  242 

Degree  required  for  ore  sampling.  ..  293 

Crystallization  of  zinc 135 

Culling  of  ore 237 

Cumberland.  England,   xinc  mines..  20S.   220 


Cutting  down  of  ore  samples...  :>in 

Cyanide  process  of  gold  extraction 5t» 

Character  of  zinc  required  in 140 

Use  of  zinc  in .  1 3* 


Dana,  on  nomenclature  of  zinc  ores. .  .  170 

Daniell,  on  ignition  point  of  zinc 135 

on  melting  point  of  zinc 134 

Dauphiny,  zinc  deposits  of 211 

Davidhutte,  Silesia   9,  10 

Daviot,  Hugues   285 

Davis,    F.    M.,    Iron    Works,    Denver, 

Colo.    299 

Dehydration  of  zinc  chloride 164 

Zinc  sulphate   154 

Delach,  Austria,  zinc  smeltery  at '6 

Delaware  Metal  Refining  Co 21 

Delta  metal   145,  146 

Dementief 's  method  of  zinc  assay 108 

Denbighshire,  zinc  mines  of 221 

Denver,  Colo.,  magnetic  separation  at.  278 

Derwiz-Szewcow-Pomeranoff  Co.. 20,  36,  225 

Desilverization    of   lead 147 

Consumption  of  zinc  in 49 

Use  of  zinc  in 59 

Determination  of  cadmium Ill 

Iron    115 

Lead   112 

Lime   118 

Magnesia    120 

Moisture  in  ore 301 

Sulphur    121 

Sulphurous  acid  in  gas 130 

Value  of  zinc  ore 303 

Deville,  on  boiling  point  of  zinc 134 

on  reduction  of  zinc  oxide 158 

Diamagnetic   minerals    268 

Dick,  on  reduction  of  zinc  oxide 159 

Dillinger,  Bergrath 6,  8 

Dillwyn  &  Co 19 

Dimensions  of  sheet  zinc 50,  51 

Dioscorides  mentions  cadmia .».  1 

Dissociation,   heat   of 168 

Distillation   furnaces    (see  Furnaces). 

Distillation  of  zinc 157 

Doellach,  Austria,  zinc  smeltery  at.  ...  6 

Dombrowa,  Russia,  zinc  works 20,  36 

Donnersmarck,  Count  Henckel  von..  10,  18 

Dony,  Daniel 4,  50 

Dortmund,  Germany,  zinc  works 19 

Drewson's  method  of  assaying  zinc  dust  129 

Drinker,  H.  S 195 

Dryer,  Edison 277 

Dubouchet,   Monsieur    18 

Ductility  of  zinc 135 

Dumont  et  Freres 17 

Durability  of  zinc 137 

Durand.  Prof.,  on  aluminum  zinc  alloys  142 

Dust,  zinc  (see  also  Zinc  Dust) ...  .57,  60 

Production  of   72 

Dutch  metal   144 

Dynevor   Spelter  Co 19 

E 

Edelmann,    on   separation   of   lead   and 

zinc    ....139 

Edes,  Mixter  &  Heald  Zinc  Co 21, 

198,  199,  200 

Edgar  Zinc  Co 21.  47 

Edison  dryer   277 

Edison  system  of  fine  crushing 278 

Eifel  district,  Germany,  zinc  mines 214 

El  Akhouat  mines,   Tunis 2 

Electric   calamine    J7h 

Electrical  properties  of  zinc !»*» 


318 


INDEX. 


PAGE 

Electrolytic  assay  for  zinc 110 

Decomposition   of  zinc  chloride....  164 

Emmons,   S.  F 183 

on  fluorspar  deposits  of  Kentucky.  .  183 

Emmons  sludge  system 248 

Empire  Zinc  Co 21,  22,  39,  278 

Ems,  Germany,  zinc  mines 213 

Endless  belts  for  ore  sorting 240 

Engis,  Belgium,  smelting  works  at. .  .6,  17 
England   (see  Great  Britain). 

English  Crown  Spelter  Co 19,  23 

English  method  of  smelting 23 

Equivalent  prices  of  spelter 84,  85 

Erbium    133 

Erste   Bb'hmische   Zinkhiitten    u.    Berg- 

bau  Gesellschaft 17 

Eschweiler,  Germany,  zinc  works 19 

Escombrera-Bleyberg,   Soc.  Anon.  d'...  17 

Europe,   ore  sampling  in .  302 

Production    of   spelter 71 

Zinc  ore   64 

Purchase  of  ore  in 303 

Zinc  ore  deposits  of 207 

European  zinc  smelters,  list  of 17 

Eustis,  on  magnetic  sulphide  of  iron .  .  259 

Expansion   of   zinc 136 

Exploration  of  American  zinc  deposits, 

first   dates   of 179 

Exports  of  zinc  from  Europe 77 

Exports  of  zinc  ore  from  Spain 226 

from  the  United  States 70 


Fages,  E.  de,  on  ore  deposits  of  Tunis.    228 

Fairbanks'  moisture  scales 302 

Falding,   F.   J » .    131 

Fanny  coal  mine,  Silesia 8 

Fanny  Franzhutte,  Silesia 18,     91 

Federal  Lead  Co.,  Mo 244 

Fedj-el-Adoum  mines,  Tunis 228 

Ferraris,  E.,  on  magnetic  separation  of 

minerals    260 

Ferraris  magnetic  separator 261 

Ferrate  of  zinc 163 

Ferric  oxide,  conversion  to  magnetic.  .    259 

Ferriferous  blende 172 

Ferrocyanide  assay  for  lead 115 

for  zinc   94,  103 

Ferrous   carbonate,  dissociation  of.  ...    260 

Ferrogoslarite    173 

Fire  brick,  cost  in  the  United  States.  .      46 

Fire  clay,  cost  in  Belgium 28 

Germany   

Silesia    33 

United   States    46 

Wales 34 

Finland,   zinc  ore  from 172 

Firket,  Ad : .  29,     30 

on  composition  of  Sardinian  zinc  ore  224 

Fizeau,  on  expansion  of  zinc 136 

Flat  River,  Mo.,  ore  dressing  practice  at  251 

Flintshire,   zinc   mines   of 221 

Florahtitte,    Silesia    18,     91 

FICne  smeltery,  Belgium 6,  17,     23 

Fluid  density  of  zinc 134 

Fluorides  of  zinc 167 

Fluorspar  deposits  of  Kentucky 183 

Occurrence  with  blende 182 

Foehr,  on  use  of  zinc  in  lead  refining. .     60 

Fohr,  on  tin  in  spelter 140 

Formation,  heat  of 168 

Formulae  for  valuing  zinc  ore 305 

Foxdale  zinc   mines 220 

Fraenkel,  A.,  on  assay  of  zinc  dust. . . .   129 

France,  character  of  zinc  ore 29 

Consumption  of  zinc 77,  78,     80 

Cost  of  coal 30 


PAGE 

Imports  and  exports  of  ore 66 

Production  of  spelter 71,     72 

Zinc  ore   64,  211 

Zinc  industry  of 30 

Zinc  ore  deposits 208,  210 

Zinc  smelters  of 18 

Franco-Belgian  coal  fields 25 

Franklin     Furnace,     N.     J.,     magnetic 

separation   at    277 

Zinc  mines 172,   178,  190 

Franklinite    174 

Assay  of   101 

Magnetic  separation  from  willemite  267 
Frankfurt,  average  price  of  spelter  at  84 

Franzhutte,    Silesia    18,     91 

Eraser  &  Chalmers 238 

Freiberg,  Saxony,  character  of  blende.    233 

Tin  in  spelter  from 140 

Zinc  mines    214 

Zinc  smelting  works 19 

Freight  rates  in  Belgium 25 

on  spelter  in  the  United  States.  ...      82 

on  zinc  ore,  Mexico  to  Europe 206 

Greece  to  Antwerp 36 

St.  Louis  to  Kansas 46 

French  zinc  ore,   composition  of 29 

Fresenius'    method     of    assaying    zinc 

dust    129 

Friedenshutte,   Silesia,  smeltery  at....      18 
Friedensville,  Pa.,  zinc  mines. 375,  178,  195 

Zinc  works   14 

Friedensville   Zinc    Co 21 

Fridrichshutte,    Silesia    18,     91 

Rolling  Mill   12 

Friedrichssegen,   ore   dressing   practice, 

214,  262 

Magnetic  separation   263 

Fuchs,   Ed 35 

Fuel   (see  also  Coal  and  Gas). 

Kinds  used  by  American  smelters.  .  21 
Fume  collection  by  bag  apparatus....  13 
Funk  on  sulphur  and  carbon  in  spelter.  141 

Furman,  H.  van  F 94,  95,  113,  115,  123 

Furnaces    (see  also  Roasting  Furnaces, 
Distillation   Furnaces,   etc.). 

at  Valentin-Cocq.,  Belgium 10 

Calcining    263,  264,  265 

Carinthian    6 

Early   Silesian    9 

English    7,     23 

Number   in   Belgium 28 

Number  of  retorts  in  distillation ...      24 

Regenerative    35 

Siemens   10,  11,     23 

Silesian    8,       9 

Type   used    in   Kansas 39 

Welsh-Belgian    34 

Fry  process   22 


Galena,     Kan.,     occurrence     of     white 

blende  at   1 72 

Zinc  mines    1 83 

Galena  ore,  grade  produced  at  Joplin.  .    188 

Occurrence  in  Silesia 216 

Galmei    173,  176 

Origin  of  name 170 

Galvanized  sheet  iron,  decay  of 52 

Galvanizing   140,  147 

Consumption  of  zinc  for 49 

Use  of  zinc  chloride  in 165 

Invented  by  Crawford 48 

Use  of  zinc  in 60 

Ganelin,    Solomon    152 

Garnet  associated  with  blende 195.  230 

Gas  firing  in  Belgium 27 

in  France   30 


INDEX. 


319 


Gas  from  furnaces,   sampling  of. 

Gas   (natural)  at  lola,  Kan 

Cost  in  Indiana. 


PAGE 
.  131 
.  15 
.  39 

Supply   of    43 

Used  for  smelting  in  Kansas 40 

Utilization  in  the  United  States 25 

Gas    (producer),   cost  of 44 

Gascony,  zinc  deposits  of 211 

Gates   crushers    242 

Gauges  of  sheet  zinc 51 

Geological   occurrence  zinc   ore   in   Eu- 
rope     : 208 

in  the  United   States 179 

Geology  of  natural  gas  fields 43 

Silesian    zinc   deposits 215 

Wisconsin    zinc   deposits 203 

Georgenberg  mine.  Silesia 219 

Georgi,  erected  zinc  works  in  Wisconsin     14 

Georgi,  Max   9 

Georgshiitte,   Silesia 8,   9,  140 

Gerlach,    on    specific    gravity    of    zinc 

sulphate    153 

German  silver    146 

Germany,   average   price   of  spelter   in, 

84,  86,     87 

Cost  of  coal 31 

Fire  clay   :S1,     33 

Consumption  of  zinc 78,     80 

Imports  and  exports  of  zinc  ore. 68,  226 

Production  of  zinc  ore 64 

Spelter    71,  72,     73 

Zinc  sulphate    91 

Wages  of  labor 31,     33 

Zinc  deposits  of 212,  208 

Industry  of   30 

Smelters  of   18,     19 

Giesche,  Georg  von 7 

Giesche's  Erben 8,   10,   18,     88 

Girard,  Kan.,  smelting  works  at 21 

Girard  Smelting  Co 21,  22,     47 

Girard  Zinc  Co 22 

Gladbach,  Germany,  smelting  works.  .  .      19 

Zinc  mines    208,  214 

Glasgow,  Scotland,  zinc  works 19 

Glauber  refers  to  zinc 2 

Glucinum  (see  Beryllium). 

Godullahiltte,    Silesia    18,     91 

Gold,  cyanide  process  of  extracting...      56 

Gold-zinc  alloys    144,  147 

Goslarite    173 

Goslar,    Germany,   nines   near 212 

Manufacture   of   brass 3 

Zinc  vitriol 138 

Gouyard,  G.  M.,  on  magnetic  sulphide  of 

iron    259 

Grade  of  Silesian  zinc  ore 217 

Ore   smelted  in   Belgium 30 

Granada,  production  of  zinc  ore 37 

Granby,  Mo.,  zinc  mines 183.  187,  188 

Grand  Calumet  Mining  Co.,  Canada.  .  .    205 

Grandfils  and  Binon 6 

Graphical  purposes,  use  of  zinc  for.  . .    139 
Gravimetric  determination  of  sulphur.    121 

Zinc   94,  110 

Gravity   concentration    241 

Great  Britain,  character  of  zinc  ore.  .      29 

Consumption  of  zinc 78,     80 

Cost  of  coal 34 

Fire  clay 34 

History  of  zinc  smelting  in 7 

Imports  of  zinc  ore  from  Spain ....    226 

Production  of  zinc  ore 64 

Spelter    71,     72 

Rate  of  wages 34 

Smelters   of    19 

Zinc  industry   in 34 

Ore  deposits   208,  221 

Great  Laxey  Mining  Co.,  England 221 


PAGE 

Greece,  character  of  zinc  ore 29 

Production  of  zinc  ore 64 

Zinc  industry  in 35. 

Ore  deposits    208,  221 

Greenway,  on  grade  of  Broken  Hill  ore  230 
on   magnetic   separation   at   Broken 

Hill 284,   285 

Grid  sampler    .    295 

Grillo,  W 19,     32 

Grinder,  sample 294 

Guerrouma  mines,  Algeria 228 

Guidottohutte,  Silesia   18,     91 

Guipuzcoa,  production  of  zinc  ore ....     37 
Gun  metal    146 

H 

Halberstadt,  average  price  of  spelter  at     84 

Hall,  E.  J 104 

Hamborn-Neumuhl,        Germany,       zinc 

works    19,  32 

Hamburg,  average  price  of  spelter  at. .  84 

Hammam  N'bails  mines,  Algeria 228 

Hammers  for  breaking  ore 236 

Hand-jigging,  cost  of 252 

Hand-sampling    294 

Hand-sorting  of  ores 233,  237 

Hanover,  N.  M.,  zinc  mines  at.  178,  194,  212 

Hardness  of  zinc 135 

Hardness,   scales   of 136 

Hardhead    144 

Hard  zinc   144 

Hartmann  mine,  Penn 195,  196 

Harz  jigs   243 

Harz  Mountains,  zinc  deposits  of 212 

Manufacture  of  zinc  vitriol 138 

Zinc  mines  of  the 208 

Haworth,  Erasmus   90- 

on  Joplin  ore  deposits 190 

Heats  of  formation  of  zinc  compounds.  167 

Heating  value  of  American  coals 42 

Hedburg,  E.,  on  cost  of  milling  at  Jop- 
lin     252 

Hegeler,   E.  C 14 

Helena  mill,  Wis 256 

Helena  Mining  Co.,  Mexico 206 

Hemimorphite    170,  176 

in  Missouri    188 

Hempel,  Prof.  W 157 

Henckel,  Count 7,  10 

Henckel  smelts  zinc  from  calamine. ...  3 

Henrich,  Carl    187,  190 

on  ore  dressing  at  Joplin,  Mo 250 

Herapath,  on  iron  in  spelter 140 

Heusschen   process    258 

Heycock,  on  melting  point  of  zinc.  . . .  134 
Himmelfahrt  ore  dressing  works,   Sax- 
ony      215 

Hobson   and   Sylvester 136 

Hofman,  H.   0 60,  149 

Hohenlohehiitte,    Silesia    18,  91 

Holibaugh,   J.    R.,   on   grade   of  Joplin 

zinc    ore    188 

Holland  (see  Netherlands). 

Holkyn   mine,   Wales 221 

Hollunder,   on  zinc  smelting  in   Carin- 

thia    6 

Holzappel,  Germany,   zinc  mines 213 

Horn  silver  mine,  Utah 200 

Hoskold,   H.   D 307 

Howard  stirrer  and  press 60 

Howe,  on  magnetic  sulphide  of  iron.  .  259 

Howe  moisture   scales 302 

Hugohiitte,  Silesia 9,  18,  23,  91 

Hugo  mine,  Silesia 218 

Hugueny,  on  hardness  of  zinc 136 

Hungary,  consumption  of  zinc 77,  80 

Production  of  zinc  ore 65 


320 


INDEX. 


liurter,   F . 

Hydrate   of   zinc 160 

Hydrocarbonates  of  zinc 161 

Hydrogen  reduces  zinc  oxide 158 

Hydrozinkite    175 

Hydroxide  of  zinc 160 

Hypochlorite   of  zinc 160 

Hyposulphite  of  zinc 152 


Identification  of  zinc  minerals 171 

Iglesias,  Sardinia,  zinc  mines 208,  223 

Ignition  point  of  zinc .   134 

lies,  M.  W 149 

Illinois,  coal  fields 41 

First  zinc  smelting  in 14 

Production  of  spelter  in 74 

Illinois  Zinc  Co 15,  21,     52 

Imports  of  zinc  into  Europe 77 

Improvements  in  zinc  smelting 24 

Impurities   in   zinc 138 

Effect  of 135 

Impurities  in  zinc  ore 290,  312 

Indiana,  natural  gas 44,     45 

Production    of  spelter 74 

Zinc  smelting  in 39 

Wages   in    46 

Indianola   Zinc   Co 21 

Indicators  for  zinc  titration ....  94,  95, 

99,   103,   104,  105 

Indigo  auxiliary    60 

Indium,  as  impurity  in  spelter 140 

Ingalls  Zinc  Co 21,  198 

Iodides  of  zinc 166 

lola,  Kan.,  discovery  of  gas  at 15 

Natural  gas  field 43,     44 

Smelting  works  at 21,     38 

Iowa,  production  of  zinc  ore 70 

Zinc   ore   deposits 203 

Iron  as  impurity  in  spelter 139,  141 

Assay  of   115 

Decomposes  zinc  sulphide 150 

Influence  in   zinc  distillation 150 

in  spelter,  determination  of 126 

in  zinc  ore,  penalty  for 310,  312 

Magnetic   sulphide    259 

Reduces  zinc  oxide 158 

Tenor  of  black  blende 233 

Iron  ore,  analyses  of  Silesian 219 

Production  in  Silesia 67 

Iron-zinc  alloys    144 

Iserlohn,  Germany,  zinc  mines ....  208,  220 

Ore   dressing   practice 257 

Isle  of  Man,  zinc  mines 220 

Isle  of  Man  Mining  Co.,  England 221 

Italian  zinc  ore,   composition  of 29 

Italy,  consumption  of  zinc 79,     80 

Production  of  zinc  ore 64,  225 

Smelters  of   19 

Zinc  industry  of 36 

Ore  deposits    208,  223 


James,  Christopher 150 

Jastrow,  H.  R.,  on  zinc  deposits  of  Tur- 
key        227 

Jedlitze  rolling  mill,  Silesia 18 

Jenney,  W.  P.,  on  Joplin  ore  deposits, 

183,  190 

Jensch,  Edmund   96,  111 

•  on  cadmium  in  zinc  ore 172,  174 

on  chlorine  in  spelter 141 

on  composition  of  Silesian  zinc  ore.    218 

on  iron  in  spelter 139 

Jersey  City.  N.  J.,  smelting  works  at  14,     20 
Jernegan.  on  use  of  zinc  in  lead  refining     60 


Jigging    

Cost  at  Joplin,  Mo 

Jigs    

Cooley  type   

Johnson,  on  expansion  of  zinc 

on  thermal  conductivity  of  zinc. . . . 

Joint  clay    

Jones,   Richard    

Jones,    Samuel   T 

Jones'   sampler 294,   296, 

Joplin,  Mo.,  average  price  of  zinc  ore, 

89, 
Smelting  works  at 

Joplin  district,  Mo.,  first  output  of. .. . 
Mining  conditions   ...  .  .  188 

Yield  of  ore  milled 

Ore  dressing  practice 243,  244, 

Purchase  of  ore  in 291, 

Magnetic  separation  in 278, 

Production  of  lead  and  zinc  ore 
Zinc  ore 45,  75,  178, 

Joplin  Separating  Co 

Juliushutte,  Germany    


PAGE 
243 
252 
243 
246 
136 
136 
176 
13 
14 
297 

90 
21 

15 
189 
253 
246 
303 
289 
188 
183 
288 
213 


Kanguet  and  Tout  mines,  Tunis 228 

Kansas,  coal    184 

Coal  fields 42 

Natural  gas 43,  184 

Ore  dressing  practice .-.   246 

Production  of  spelter 16,     74 

Zinc  ore 69,  176,  188 

Smelting  conditions  in 39 

Wages  in    46 

Zinc  deposits  of 178,  179.  183,  184 

Zinc  smelters  of 184 

Kansas  Zinc  Mining  &  Smelting  Co 22 

Karl  Gustav  mine,  Silesia 218 

Karmasch,  on  strength  of  zinc 137 

Karsasu,  Turkey,  zinc  mines  near 227 

Karsten,  on  effect  of  iron  in  spelter. .  .    139 

on  effect  of  tin  in  spelter 140 

on  specific  gravity  of  zinc 134 

Kemp,   J.   F.,   on   New   Jersey   zinc  de- 
posits       192 

Kenngott    introduces    name    hemimor- 

phite    170 

Kentucky,  zinc  ore  deposits 178,  182 

Kenyon,  H.  &  Co 19 

Kern,  Sergius,  on  nickel-bronze 147 

Klein  Dombrowka,  Silesia,  smeltery  at.      18 
Klemp's  method  of  assaying  zinc  dust..   128 

Knaps'  method  of  zinc  assay 110 

Knaut,   Hiittenmeister    9 

Knight,  F.  C.,  method  of  lead  assaying  113 
Knowles  &  Cleveland  magnetic  separa- 
tor        285 

Koeniglichen    Friedrichs    Bleihiitte,    Si- 
lesia            8 

Koenigs-Eisenhiitte,  Silesia    8 

Koenigshutte,   Silesia,  zinc  works  at...        8 

Konkordiahiitte,   Silesia    8 

Kokomo,  Colo.,  zinc  mines 178,  182,  233 

Kolbech,  on  occurrence  of  tin  with  zinc  138 

Komorek,  on  boiling  point  of  zinc 134 

Koninck,  L.  L.  de 104 

Kosmann.  on  a  remarkable  spelter.  .  .  .    140 
on  value  of  zinc  ore  in  Silesia ....    308 
Kremers.    on    specific    gravity    of    zinc 

chloride    * 166 

Kuehn.  on  basic  zinc  sulphate 155 

Kunhardt,    W.    B.,    on    ore   dressing   in 

Europe    258 

Kunigundehiitte.    Silesia    18.     91 

Kunzel,  on  chlorine  in  spelter 141 


INDEX. 


321 


PAGE 

Labor,  cost  in  Belgium 28 

Wales    34 

in  roofing  with  zinc 54 

in  sheet  zinc  rolling 28 

Kate  of  wages  at  Joplin,  Mo 248 

Silesia,  Germany 11,  31,  33,  246 

United  States    46 

La  Florida  mines,  Spain 226 

La  Harpe,  Kan.,  smelting  works  at.  ...  21 

Laminne,  L.   de 17 

Langguth,  on  magnetic  permeability  of 

minerals    269 

Langmuir,  A.  C 99,  125,  127 

Languedoc,  zinc  deposits  of 211 

Lanyon  Bros.'   Spelter  Co 21 

Lanyon,  Robert   15 

Lanyon,  Robert  &  Co 22 

Lanyon  (Robert)   Sons  Spelter  Co 22 

Lanyon,  S.  H.,  &  Bro 21 

Lanyon,  W.  &  J 22 

Lanyon  Zinc  Co 21,  22,  47 

Lasalle,  111.,  smelting  works.  14,  21,  39,  41 

Latourette,  James   21 

La  Trieuse  magnetic  separator 285 

Laur,  Francis    71 

Laurenberg  ore  dressing  works 214 

Laurie,  on  composition  of  brass 144 

Laurium,  Greece,  zinc  mines. .  .35,  208,  221 

Magnetic  separation  at 285 

Lautenthal,   Germany,  zinc  mines 212 

Lawson,   Dr.   Isaac 3 

Lazyhutte,  Silesia   18,  91 

Lead,  as  impurity  in  spelter 138 

Assay  of 112 

Desilveration  of 147 

Consumption  of  zinc  for 49 

Use  of  zinc  in 59 

in  spelter,  determination  of -126 

in  zinc  ore,  penalty  for 310,  312 

Recovery  from  zinc  ore 312 

Lead  and  zinc  smelteries  in  Belgium..  17 
Lead    Mine    Bend,    Tenn.,    zinc    mines, 

178,  197,  199 

Lead  ore  production  of  Greece 221 

Joplin  district    221 

Silesia    67 

Greece    221 

Lead  smelting  at  Broken  Hill 230 

Leadville  blende,  magnetic  permeability 

of   269 

Leadville,  Colo.,  ore  dressing  practice..  243 
Zinc  mines  and  ore.  .  .  .70,  178,  181, 

213,  233 

Lead-zinc  alloys 145 

Leasing  system  at  Joplin 189 

Le  Chatelier  on  dissociation  of  ferrous 

carbonate    260 

Lefort,  on  zinc  carbonates 162 

Legal  Tender  mine,  Arkansas 180 

Lehigh  coal  field 41 

Lehigh  Zinc  and  Iron  Co 22 

Lehigh  Zinc  Co.,  Penn.  .  .  .14,  140,  267,  269 

Lemery,  on  zinc 2 

Les  Malines   (see  Malines). 

Letmathe,   Germany,  zinc  works 19 

Libavius.  on  the  properties  of  zinc 2 

Lidner,  P.  G.,  on  ore  dressing  at  Amme- 

berg   227,  256 

Liebehoffnungshutte.    Silesia 9,  18,  91 

Liege  coal  basin.  Belgium 26 

Lill   dressing  works,    Bohemia 262 

Limburg,   Holland,   smelting  works....  20 

Lime,   assay  methods   for 118 

Influence  in  zinc  distillation 149 

Limitation  of  the  use  of  zinc 61 

Limonite    produced    with    zinc    ore    in 

Virginia    202 


PAGE 

Lindner,  A 219 

Lintorf,  ore  dressing  practice  at 257 

Lipine,  Silesia,  smelting  works 9,  18 

Rolling  mill    18 

Liskeard,  Cornwall,   zinc  mines 220 

List  of  American  zinc  smelters 20 

Loebbeckeschen,   Hugo  von,   Zinkhiitten  17 
Lohmannsfeld,  Germany,  magnetic  sep- 
aration at    279 

Lombardy,  zinc  mines 223,  225 

London  as  a  spelter  market 82 

Average  price  of  spelter  at.  .83,  84, 

86,  87 

Losses  in   ore   dressing 241 

at  Joplin    249 

Loss  of  zinc  in  smelting 10 

Low,  A.  H 94,  99,  111 

Lower  Harz   (see  Harz  Mountains). 

Lunge,  G 131 

Lungwitz,  E 156,  157 

Lydogniahiitte,  Silesia 8,  9,   12,  91 

Lysaght,  John.  Ltd 19 

M 

Maestricht,  Holland,  smelting  works.  .  20 

Magnesia,  assay  methods  for 120 

Magnesium    133,  159 

as  impurity  in  spelter 140 

Magnetic  oxide  of  iron 259 

Magnetic  separation   233,  258 

in  Arkansas    180,  288 

at  Austinville,  Va 276 

at  Broken  Hill 284 

Convers  process   267 

at  Denver,  Colo 278 

at  Friedrichssegen   214,  263 

at  Lohmannsfeld,   Germany 279 

at  Joplin,  Mo 278,  289 

at  Laurium,  Greece 285 

at  Monteponi    224 

in  New  Jersey 277 

at  Rico,  Colo 182 

Wetherill  process    15 

Magnetic  separator,   Cleveland-Knowles  285 

Ferraris    261 

La  Trieuse   285 

Siemens    262 

Wenstrom    266,  268 

Wetherill    269 

Magnetic  sulphide  of  iron 259 

Magnetic  Separating  Co.,  Joplin,  Mo. . .  289 

Magnetism   of  minerals 268 

Magnus,   Albertus    2 

Mahler,  P.,  on  blende  roasting 154 

Malagalzetta  mines,   Sardinia 224 

Malapane  rolling  mill.  Silesia 12,  18 

Malfidano   mines.    Sardinia 223 

Malfidano.  Societe  des  Mines  de.18,  30,  223 

Malines,  France,  zinc  mines 208,  211 

Malleability  of  zinc 135 

Manganese,  determination  of 101 

in  zinc  ore,  penalty  for 312 

Manganese  bronze    147 

Manganiferous  smithsonite    173 

Zinc  ore,  assay  of 101 

Mannheim  gold    146 

Manning  &  Squier.  zinc  mines 200 

Manual  selection  of  ores 233,  237 

Map  of  Belgium 26 

Marboutin,   Felix,   on  determination   of 

sulphur    123 

Marcasite.  in  Joplin  zinc  ore 188 

Separation  from  blende 256 

in  Silesian  zinc  ore 217 

Marchasita  aurea    2 

Margraaf's  experiments   4 

Marie  mine.   Silesia 13,  88 


322 


LNDEX. 


PAGE 

Marion,  Ind.,  smelting  works  at 21,  39 

Marion,  Ky.,  zinc  mines  at 178,  182 

Markets  for  spelter 82 

Markisch-Westfalischen       Bergwerksve- 

rein    19 

Marmatite    172,  233 

Mascot,  Tenn.,  zinc  mines 197 

Matthiessen,   on  electrical   conductivity 

of  zinc   136 

on  specific  gravity  of  zinc 134 

Matthiessen   &   Hegeler 14 

Matthiessen  &  Hegeler  Zinc  Co.  .21,  42, 

52,  203,  256 

Meade,  P.  K.,  method  of  zinc  determi- 
nation      109 

Mechanical   sampling    298 

Meier,  F.,  on  boiling  point  of  zinc 134 

Melting  point  of  zinc 134 

Mendele"ef,  periodic  classification  of  ele- 
ments     133 

Mercury,  atomic  weight 1 33 

Mercury-zinc  alloys   145 

Merglon,   France,    zinc  mines 211 

Merklin,  Austria,  zinc  works 17 

Merton,  Henry  R.,  &  Co 62,  72,  73,  77 

Metallgesellschaft,  Frankfurt  am  Main, 

63,  76,  77,  80,  83,  84,  269 

Methods  of  laying  sheet  zinc  roofs.  ...  52 

Meunier,  J 110 

Mexico,   zinc  ore  deposits 205 

Meyer,   V.,   on  specific  gravity   of  zinc 

vapor    134 

Michalkowitz,  Silesia,  smeltery  at 18 

Microscopical  investigation  of  zinc.  . .  .  139 

Midland  Smelting  Co.,  Kansas •  21 

Mill  of  Colorado  Zinc  Co.,  at  Denver.  .  278 

N.  J.  Zinc  Co.  at  Mine  Hill 277 

Magnetic  separating,  at  Lohmanns- 

feld , 279 

Miller,  E.   H 104 

on  assay  of  cadmium 112 

Milling,  cost  of  at  Broken  Hill 230 

Methods  in  Joplin  district 246 

Mills,   concentrating,  arrangement  of.  .  244 

Cost  in  Joplin  district 248 

Mine  Hill,  N.  J.,  zinc  mines 190 

Magnetic  separation  at 277 

Minera  mines,  Wales 221 

Mineral  Point,  Wis.,  zinc  mines 203 

Mineral  Point  Zinc  Co.,  Wis 21,  22,  39 

Mineralogy  of  zinc  ores 171 

Minerals,   relative  magnetism  of 268 

Mines,    cost    of    developing    at    Joplin, 

Mo 253 

at  Laurium,  Greece 35 

of  Poland   36 

Mining  conditions  in  Greece 35 

in  Joplin  district 188,  189 

in   New  Jersey 193 

in  Tennessee   200 

in   Silesia    219 

in  Wisconsin    204 

in  Virginia 201,  202 


Mining,  cost  at  Broken  Hill 230 

Joplin,  Mo. 


252 


Tasmania    231 

Minsterley,   England,  zinc  mines 221 

Missouri,  first  zinc  works 15 

Ore  dressing  practice 246 

Production  of  spelter 16,  74 

Spelter,   composition   of 140 

Value  of  calamine 304 

Zinc  and  lead  ore 69.  188 

Zinc  deposits  of..  176,  178,  179,  183,  184 

Smelters  of   184 

Missouri  &  Kansas  Zinc  Miners'  Asso- 
ciation      309 

Missouri  Zinc  Co. .  .  21 


Moctezuma  Copper  Co. 
Moh's  scale  of  hardness . 


PAGE 

250 

136 

Moisture  in  ore,  determination  of 301 

Molybdate  assay  for  lead 112 

Monosulphite  of  zinc 152 

Mons  coal  basin,  Belgium 26 

Monteponi,  magnetic  separation  at.  ...  260 

Monteponi  mines,   Sardinia 223 

Monteponi,  zinc  smeltery 19 

Monteponi,   Societa  di 19,  36 

Montevecchio  mine,   Sardinia 224 

Montezuma,  C9lo.,  zinc  mines  at 182 

Montgomeryshire,   zinc  deposits  of.  ...  221 

Monheimite    173 

Mosaic  gold    146 

Mosselman,   Dominique    5,  50 

Mossinoacian  copper    1 

Mossy  Creek,  Tenn.,  zinc  mines.  .  ..178,  197 

Moresnet,  zinc  ore  deposits 2,  208,  209 

Production  of  zinc  ore 65 

Morgenroth,   Silesia,  smeltery  at 18 

Morning  Star  mine,  Arkansas 180 

Morse,  on  properties  of  zinc  sulphide.  .  151 
Moxham,  E.  C.,  on  zinc  mining  in  Vir- 
ginia     202 

Moyer  mine,  Leadville,  Colo 181 

Muldnerhiitte,  Saxony   19 

Muntz's  metal 58,   59,  144 

Murcia,  production  of  zinc  ore 37 

Zinc   deposits    226 


N 


Nacosari,  Mex.,  ore  dressing  practice  at 

Nails  for  sheet  zinc 

Nason,   F.  L.,   on  New  Jersey  zinc  de- 
posits    192, 

Nassau,  ore  deposits  of 

Native  zinc,  occurrence  of 

Natural  gas   (see  also  Gas). 


Neath,  England,  zinc  works 

Nebida  mines,  Sardinia 

Neodesha,  Kan.,  smelting  works  at.  ... 
Netherlands,  consumption  of  zinc 

Production  of  spelter 71, 

Smelters  of    

Zinc  industry  of 

Neue  Helene  mill,  Silesia 

Neue  Helene  mine,  Silesia 217,  218, 

220, 

Neuhof  mine.  Silesia 

Neuhof  ore  dressing  works,  Silesia .... 

Neumann,  B 

Neumiihl-Hamborn,  Germany,  zinc 

works  

Neuthead,  England,  zinc  mines 

Nevada,  Mo.,  smelting  works  at 

Neville,  on  melting  point  of  zinc 

Newark,  N.  J.,  zinc  works  at 14, 

New  Caledonia,  zinc  ore  deposits 

New  Jersey,  mining  conditions 

Production  of  ore  and  spelter. .  .16, 
69,  74, 

Wages  in 

Zinc  ore 13,  174,  175, 

Composition  of 193,  267, 

Deposits 178,  179, 

New  Jersey  Zinc  &  Iron  Co 

New  Jersey  Zinc  Co.  .14,  20,  22,  37,  47, 
103,  181,  190, 

New  Market,  Tenn..  zinc  mines 

New  Mexico,  zinc  deposits  of.  .178,  179, 

New  Minera  mine,  Wales 

New  South  Wales,  production  of  zinc 
ore 64, 

Zinc   deposits    


250 
52 

193 
213 
177 

184 
19 

224 
21 
80 
73 
20 
36 

245 

245 

218 
217 
106 

19 
220 

21 
134 

20 
231 
193 

194 

46 

176 

278 

190 

22 

277 
197 
194 
221 

69 

229 


INDEX. 


323 


New  York  as  a  spelter  market 82 

Average  price  of  spelter  at . .  83.  86,  87 
Nicholson,  F.,  on  cost  of  zinc  ore  pro- 
duction at  Joplin 252 

Nicholson.  Geo.  E 21,  22 

Nickel  bronze 147 

Niedzieliska.  Austria,  zinc  works 17 

Nissenson,  H 106 

Nitze,   H.   B.   C 273,  275 

Nomenclature  of  zinc  ores 169 

Nordmark,  Sweden,  occurrence  of  white 

blende 172 

Normahutte.  Silesia   18,  91 

North  American  Ore  &  Metal  Co 180 

Northwestern     Railway     Station,     Bir- 
mingham, England 52 

Norway,  production  of  ore 65 

Nouvelle  Montagne,  Belgium,  zinc  mines  210 

Nouvelle  Montagne,  Soc.  Anon,  de  la.  .6,  17 
Noyelles-Godault,    France,    zinc    works 

at,    18,  30 


Oberhausen,  Westphalia,  rolling  mill ...  19 

Oberlahnstein.  ore  dressing  practice  at.  258 
Oberschlesischen      Eisenbahn      Bedarfs 

Aktiengesellschaft   18 

Ogdensburgh,  N.  J.,  zinc  mines 190 

Ohlau  rolling  mills.  Silesia 18 

Oker,  Germany,  mines  near 212 

Old  Jim  mine,  Kentucky 182 

Olkusz  mines.  Poland 225 

Ore,  amount  smelted  in  Belgium 28 

Average  grade  smelted  in  Belgium.  .  30 

Grade  of  Joplin 90 

Price  at  Joplin 89,  90 

Breaking   234 

Hammers  for 236 

Classified  by  grade 16 

Character  of  American 45 

Composition  of  European 29 

Crushing    235,  242 

Deposits  of  Canada 205 

Joplin,  nature  of 183 

Mexico 205 

Dressing,    cost    in    Joplin    district, 

248,  252 

Degree  of  concentration  in 232 

Relation  to  smelting 253 

Practice  at  Ammeberg 227,  256 

Broken  Hill 230 

Friedrichssegen 262 

Germany   214 

Iserlohn    257 

Lintorf   257 

Nacosari,  Mexico 250 

Missouri  and  Kansas 246 

Monteponi 260 

Oberlahnstein,  Prussia 258 

Rico,  Colo 182 

Sardinia   223,  224 

Silesia  217,  244,  246 

Southeast  Missouri   251 

Wisconsin    256 

Dryer,  Edison 277 

Grade  of  Silesian 10 

Methods  of  purchase 291 

Production  in  Europe 64 

New  Jersey 194 

Joplin  district 188 

Silesia    7,  67 

Spain   37 

Purchase  of 312 

Sampling 291,  292 

Screening 243 

Shipments  from  Cartagena.  Spain..  226 


PAGE 

Sorting 233 

at  Ammeberg 227 

Endless  belts  for 240 

in  Greece 35 

Picking  tables  for 237,  239 

Supply  of  American  smelters 45 

of  Belgian  smelters 25 

of  German  smelters 31,  33 

of  Silesian  smelters 33 

Sources  of 22 

Value  of 290 

Valuation  of 303 

Ores,  analysis  of 93 

of  zinc 169 

Orton,  Edward 43 

Oruro,  Bolivia,  wurtzite  found  at 172 

Overpelt,  Belgium,  smelting  works  at. 6,  17 

Overpelt,  Soc.  Anon,  des  metaux  d'.  . . .  17 

Ougree,  Belgium,  smeltery  at 6 

Oxide  of  iron,  magnetic 259 

Oxide  of  zinc  (see  also  Zinc  Oxide) 156 

American  production 75 

Manufacture  in  Europe 75 

Production  and  consumption  in  the 

United  States 81,  82 

Production  in  Silesia 67 

by     Soc.     Anon,     de     la     Vieille 

Montagne 92 

Uses  of 61 

Value  as  pigment 48 

Oxychloride  of  zinc 159,  164 

Oxygen  as  impurity  in  spelter 141 


Packfong 146 

Page,  R.  W..  on  assay  of  cadmium 112 

Palmerton.  Pa.,  smelting  works.  .20,  38,  41 

Panchot,  France,  rolling  mill 30 

Paracelsus  describes  zinc 1 

Paramagnetic  minerals 268 

Park  City,  Utah,  zinc  ore  at 200 

Parkes  process  of  lead  desilverizing ....  59 

Parnell  process 155 

Passaic  Zinc  Co 22 

Pascoe  Greenf ell  &  Sons 19 

Pattinson  process  of  lead  desilverizing..  59 

Paul  Richard  mine,  Silesia 67 

Paulina  zinc  works,  Poland 225 

Paulshiitte,  Silesia   18,  91 

Paweck,  H.,  electrolytic  assay  of  zinc. .  110 

Paxton,  Geo.  B 310 

Paxton  scale  of  zinc  ore  prices. . .  .309,  311 

Pellet.  H 108 

Penalty  for  lead  and  iron  in  zinc  ore, 

310,  312 

Pennsylvania,  first  zinc  smelting  in 14 

Natural  gas 44,  45 

Production  of  spelter 74 

Zinc  ore  deposits  of 178,  179,  195 

Pennsylvania  &  Lehigh  Zinc  Co 195 

Percy,  Dr.  John 23 

on  properties  of  zinc 136 

on  properties  of  zinc  sulphide.  .149,  150 

on  reduction  of  zinc  oxide 158 

on  zinc  silicates 162 

Periodic   classification   of  elements....  133 

Permanganate  assay  for  iron 115 

for  lead 113 

for  lime 118 

Permeability,  magnetic,  of  minerals. .  .  268 

Person,  on  nelt'ng  point  of  zinc 134 

Peru,  111..  smelHng  works.  ..15,  21,  39,  41 

Peters.  *3.  D.,  Tr.,  in  ore  crushing.  .  235,  236 

Pettenkoffer  on  weathering  of  zinc 137 

Petty  mine.  Arkansas 180 

Philippe  le  Bon 3 


324 


INDEX. 


Phillips,    W.    B.,    on    magnetic    separa- 
tion       ....  288 

Philippeville,  Belgium,  zinc  mines 210 

Physical  Properties  of  zinc 134 

Picard,  H.  K 138 

Picard  &  Sulman  smelting  process.  . .  .  230 

Picking  tables 239 

Picos  de  Europa  mines,  Spain 226 

Piedmont,  Italy,  zinc  mines 223,  225 

Piela  rolling  mill,  Silesia 18 

Pigments,  use  of  zinc  in 48,  61 

Pilsen,  Austria,  zinc  works 17 

Pinchbeck 146 

Pittsburg,  Kan.,  smelting  works....  15, 

21,  38,  39,  40,  41 

Pittsburg  &  St.  Louis  Zinc  Co 22 

Pliny  mentions  cadmia 1 

Pluecker,  on  magnetic  susceptibility  of 

minerals   268 

Pocahontas  Flat  Top  coal  region ......  38 

Poggiale,  on  solubility  of  zinc  sulphate.  153 
Poland  (see  Russia). 

Pontpe"an  zinc  mines,  France 210 

Posepny,    F.,    on    ore   deposits    of   Lau- 

rium 222 

Potockische  Berg-u.  Hiittenverwaltung..  17 

Potosi,  Mo.,  zinc  works  at 15 

Pouget's  method  of  zinc  assay 109 

Prayon,  Belgium,  smelting  works  at.  .6,  17 

Prayon,  Soc.  Anon.  Metallurgique  de.  . .  17 

"President"  pump 196 

Price  of  (see  also  Cost). 

Coal  in  Illinois 42 

Kansas   42 

Silesia   11 

Labor  in  Silesia 11 

Sheet  zinc 28 

Spelter 9,  12,  13,  28,  38,  61,  62, 

67,  82,  83,  92 

Zinc   ore   in   Silesia 11,  68 

Prince's  metal   144 

Prime,  Frederick 195 

Prime  Western  Spelter  Co 21,  22 

Prime  Western  spelter,  average  price  of  83 
Production  of  lead  and  zinc  ore  at  Jop- 

lin   188 

Lead  by  Sulphide  Corporation 230 

in  Greece 221 

Spelter    (refer   also   to    States    and 
Countries). 

in  Russia 36 

in  Silesia 91 

Zinc  ore  in  Canada 205 

France 211 

Italy    225 

Joplin,  Mo 252 

Moresnet 209 

New  Jersey 194 

New  South  Wales 69 

Spain .37,  226 

Turkey 227 

United  States 69 

Wisconsin    204 

Properties  of  zinc  alloys 141 

of  zinc  minerals 171 

Prost,  Eugene 104 

Provence,  zinc  deposits  of 212 

Prus,  G.,  on  magnetic  separation 262 

Prussia  (see  Germany). 

Przibramite   172 

Pueblo.  Colo.,  zinc  smelting  work  at,  21,  47 

Pulaski,  Va.,  smelting  works 20,  200 

Zinc  ore  near 178 

Pullinger,  on  action  of  acids  on  zinc.  .  137 

Purchase  of  ore 312 

Methods  of 291 

in  Europe    303 

in  Joplin  district 303 


Pyiite,     conversion    to    magnetic     sul- 
phide        259 

Production  in  Silesia 67 

Separation  from  blende 255 


Radzionkau,  Silesia,  smeltery  at 

Raibl,  Austria,  zinc  mines 175, 

Rammelsberg,  on  specific  gravity  of  zinc 

Rammelsberg  mines,  Germany 212, 

Raoour  &  Co 

R'arbou  mines,  Algeria 

Reckehiitte,  Silesia 18, 

Red  zinc  ore 

Redlichkeit  mine,  Silesia 218, 

Reducibility  of  zinc  oxide 157, 

Reduction  material,  cinder  as 

Reed,  on  ore  sampling 

Refining  lead,  use  of  zinc  in 

Refining  zinc  from  lead 

Refractory  material  (see  Fire  Clay  and 
Fire  Brick). 

Regenerative  distillation  furnaces  (see 
also  Furnaces)  

Regnault,  on  specific  heat  of  zinc 

Remsen,  Prof.  Ira 

Reocin,  Spain,  zinc  mines  of 208, 

Reuter,  Max,  on  assay  of  sulphur 

Rheinisch-Nassauischen  Akt.  Gesell- 
schaf t  

Rheinland,  smelters  of 

Rhenish  method  of  smelting 23, 

Rhenish  Prussia,  coal  resources 

Smelters 19, 

Zinc  deposits  

Production  

Rich  Hill  Mining  &  Smelting  Co 21, 

Richards,  J.  W.,  on  aluminum  zinc  al- 
loys   

Richards,  T.  W.,  on  atomic  weights.  . .  . 

Rico,  Colo.,  ore  dressing 

Zinc  mines  

Rico  Mining  &  Milling  Co 

Riffle  sampler 294, 

Rinmann  and  Cronstedt 

Rive,  A.  de  la 

Roasting  blende 148,  154, 

Blende  and  marcasite 

Roasted  ore,  determination  of  sulphates 


in 


Roasting  furnace  gas,  determination  of 

sulphurous  acid  in 

Roberts-Austen,  on  boiling  point  of  zinc 

on  expansion  of  zinc 

on  melting  point  of  zinc 

on  strength  of  zinc 

Robins  Belt  Conveying  Co 

Rock  breakers 

Rodwell,  on  impurities  in  spelter 

Roessler,  on  separation  of  lead  and 

zinc 

Rogers,  Henry  D 

Rokoko  mine,  Silesia 218, 

Rolling  sheet  brass 

Sheet  zinc 

Effect  of  cadmium 

Effect  of  lead 

Rolling  mill  at  Panchot,  France 

Rolling  mills  in  Belgium 

Russia   

Spain   

Silesia  12, 

Rolls  for  ore  crushing 

Roofing  with  sheet  zinc  in  Europe 

Roofs,  weight  of  various  kinds 

Sheet  zinc,  durability  of 

Methods  of  laying 


18 
20H 
134 
233 

20 
228 
140 
175 
219 
158 

11 
293 

59 
139 


35 
135 
164 
226 
124 

19 
19 

232 
31 
30 

214 
16 
22 

142 
133 
182 
182 
182 
295 
4 

137 
157 
256 

130 

130 
134 
136 
134 
136 
240 
24° 
141 

139 

195 

219 

59 

28 

140 

139 

30 

6 

36 

37 

18 

242 

50 

53 

52 

52 


INDEX. 


325 


PAGE 

Romanoff,    on    separation    of    lead    and 

zinc 139 

Rosamundehiitte,  Silesia 18,  91 

Roscoe  and  Schorlemmer 160 

Rosdzin,  Silesia,  smeltery  at 18 

Rose,  on  zinc  carbonates 161 

Rose,  Gustav,  on  properties  of  zinc. . . .  135 

Rose,  II.,   on  zinc  carbonates 162 

Roseberry  mine,  Tasmania 231 

Rosiclare,  111.,  fluorspar  mines 183 

Roswag,  on  use  of  zinc  in  lead  refining  59 

Roth.  II 18 

Roussan  zinc  mines,  France 211 

Rowand,   Lewis  G 273 

Royalty  on  zinc  ore  at  Joplin 189 

Rubber  manufacture,  use  of  zinc  in ....  61 

Ruda,  Silesia,  smeltery  at 18 

Rudzinitz  rolling  mill,  Silesia 18 

Ruhberg,  Johann 7,  8 

Rush  Creek  mining  district,  Arkansas .  .  179 

Russia,  consumption  of  zinc 79,  80 

Smelters  of 20 

Production  of  zinc  ore 64 

Production  of  spelter Tl,  72,  73 

Zinc  ore  deposits 208,  225 

Industry 36 

Rybnik  rolling  mill,  Silesia 12 


Sagor,  Austria,  zinc  works  at 17 

Saint  Amand,  France,  smeltery  at....  30 

Saint  Amand,  Usine  a  Zinc  de 18 

Saint  Girons,  France,  zinc  mines 211 

Saint    Jean    de    Losne,     France,     zinc 

works    18 

Saint  Leonard  zinc  works.  Belgium.. 5,  6 

St.  Louis  as  a  spelter  market 82 

Smelting  works  at 21,  38,  41 

Sakamody   mines,   Algeria 228 

Sal  ammoniac  used  in  galvanizing  iron  165 

Sambre  coal  basin,  Belgium 26 

Sample  grinder 294 

Sampling  ore 291,  292 

European  method 302 

Important  in  control  of  works 291 

Roasting  furnace  gas 131 

Sandoval,  111.,  smelting  works  at 21 

San  Giovanni  mines.  Sardinia 224 

Santander,  production  of  zinc  ore 37 

Zinc  deposits  of 175,  226 

Sardinia,  zinc  deposits  of 223 

Sardinian  ore,  composition  of 29 

Saucon  mine,  Pennsylvania 195,  196 

Saxony,  smelters  of 19 

Zinc  deposits  of 214 

Scales  of  hardness 136 

Scales  for  moisture  determination 302 

Scales,  sliding,  for  valuing  ore 305 

Scammon,  Kan.,  smelting  works  at.  ...  22 

Scammon  Zinc  Co 22 

Schaffner  method  of  determining  zinc, 

104,  106 

Schaffgotsch.  Countess   18 

Scharley  mine.  Silesia 13,  67,  88,  216 

Schiechel,  Max    273 

Schiff,   on  specific  gravity  of  zinc  sul- 
phate     153 

Schindler,  on  basic  zinc  sulphate 155 

on  zinc  carbonates 161,  162 

Schlesische        Aktiengesellschaft       fur 

Bergbau-u.   Zinkhuttenbetrieb    10,  18 

Schnabel,  Dr.  Carl..  138,  149,  150,  157,  158 

Schneeberg,  Austria,  zinc  mines 208 

Schoppinitz,   Silesia,  smeltery  at 

Schuepphaus,  R.  C 156,  157 

Schuylkill  coal  field,  Pennsylvania 41 


PAGE 

Schwarzwald,  Silesia,  smelting  works..  18 

Scorification  of  zinc 163 

Scotland  (see  Great  Britain). 

Screening  of  ore 243 

Seamon,  W.  H 49,  50,  54 

Seilles,  Belgium,  smelting  works  at.  .6,  17 

Sentein  mines,  France 211 

Separation  of  blende  and  pyrites 255 

of  blende  and  siderite 262 

of  lead  and  zinc 139 

of  minerals  by  magnetism 25H 

by  sifting   257 

Separators,  magnetic,   Wetherill 269 

Shafts,  depth  of,  at  Joplin,  Mo 189 

Shaft  sinking  at  Joplin,  Mo.,  cost  of..  190 

Shaking  tables   243 

Shavings  of  zinc  for  cyanide  process.  .  56 

Sheet  brass 144 

Sheet  zinc,  consumption  of.  .49,  78,  79,  80 

Cost  of  roofing  with 54 

Effect  of  cadmium 140 

Gauges 51 

Lead  in   139 

Microscopical  examination 139 

Miscellaneous  uses  of 57 

Production    by    Soc.    Anon.    Vieille 

Montagne 92 

in  Belgium   28 

in  Europe 90 

Roofs 50 

Methods  of  laying 52 

Solder  for 52 

Statistics  of  consumption 77,  78,  79 

Use  in  boilers 55 

in   cyanide  process 56 

Weight  of 50,  51 

Sheffield  silver 146 

Shingles,  zinc 53 

Shropshire,  zinc  mines  of 208,  221 

Shullsburg,  Wis.,  zinc  mines 203 

Siderite,  decomposition  by  heating 260 

Separation  from  blende 262 

Sidi-Ahmet  mines,  Tunis 228 

Siebengebirge,  Germany,  zinc  mines. .  . .  214 

Siegismundhiitte,   Silesia    8 

Siemens  distillation  furnace.  .9,  10,  11,  23 

Siemens,  Dr.  W.,  magnetic  separator..  262 

Sierra  Nevada  mine,  Leadville,  Colo. . ..  181 

Siersza,  Austria,  zinc  works 17 

Sifting,  separation  of  minerals  by 257 

Silberau  ore  dressing  works,  Germany .  .  214 
Silesia,    average    price    of    spelter    in, 

86,  87,  88 

Coal  resources 32 

Cost  of  coal 

Fire  clay 33 

History  of  zinc  smelting  in 4,  7 

Mining  conditions    219 

Ore  dressing  practice 217,  244,  246 

Production 67 

Supply   

Price  of  zinc  ore 68 

Production  of  sheet  zinc 90 

Spelter 16,  91 

Rate  of  wages  in 33,  246 

Valuation  of  zinc  ore  in 308 

Zinc  mines  of 3,  208,  215 

Smelters  of 18 

Yield  of  spelter  from  ore 10 

Silesian  method  of  smelting 22 

Spelter,  average  price  of 83 

Composition  of 138,  139,  140 

Zinc  ore,  character  of 174 

Silesiahtitte,  Silesia 18,  91 

Silicate  of  zinc l«g 

Silicate  of  zinc  ore,  Missouri 187 

Silicon  in  spelter 141 

Silicon  bronze    !*<> 


326 


INDEX. 


PAGE 

Silver,  boiling  point  of 134 

in  commercial  zinc 138,  140 

Recovery  from  zinc  ore 312 

Silver-zinc  alloys   145,  147 

Singay,  St.  Paul  de 2,       6 

Singay,  Gaston  St.  Paul  de 6,     27 

Slags  in  lead  smelting 149 

In  zinc  retorts 163 

Slawkow,  Russia,  rolling  mill 36 

Sliding  scales  for  valuing  ore 304 

Slime  washing 243 

Smelters  of  Holland 36 

Kansas   184 

Poland 225 

List  of  European 17 

of  American   20 

Number  in  Belgium 28 

Smelteries  of  Rhenish  Prussia 30 

Smelting,  Carinthian  process 6 

Conditions  in  Kansas 39 

Cost  of   290 

in  Silesia 9,     11 

Consumption  of  coal  in  Belgium ....      28 
Early    experiments    in    the    United 

States 14 

English  process 3,       7 

Grade   of   ore   required   by   Belgian 

method   232 

Improvements  in   24 

Iron,  zinc  in  by-products  from 219 

Lead  ore  at  Broken  Hill 230 

Relation  to  ore  dressing 253 

Systems  of 22 

with  natural  gas 43 

in  Kansas   40 

Smith,  Col.  V 52,     53 

Smithsonite   170,  173 

Arkansas 180 

Missouri   188 

Smits  on  magnetic  separation 284 

Soci6te  Anon,  de  la  Nouvelle  Montagne 

(see  Nouvelle  Montagne). 
Soci6te   Anon,    de   la   Vieille   Montagne 
(see  Vieille  Montagne). 

Soci^te"  de  la  Cambine 20 

Socie~t6    des    Mines    de    Malfidano    (see 

also  Malfidano)   223 

Socie-te"  des  Usines  du  Laurium 221,  222 

Societa  di  Monteponi 19,  36,  260 

Sodium  sulphide  assay  for  zinc.  .  .  .104,  106 

Sodium-zinc  alloy    146 

Sokolow,  N 225 

Solder  for  sheet  zinc 52 

Solubility  of  zinc 137 

Zinc  chloride 166 

Zinc  oxide 159 

Zinc  sulphate 153 

Zinc  sulphide   151 

Sophienhiitte,  Germany    213 

Sorting  ore 233,  237 

Advisability  of 241 

at  Ammeberg 227 

Cost  of 35,  240 

Sosnowice  Co 20,  36,  225 

South      Bethlehem,      Penn.,      smelting 

works 20,     41 

Southwestern  Chemical  Co 21 

Spain,  character  of  zinc  ore 29 

Consumption  of  zinc 79,     80 

Imports  and  exports  of  zinc  ore 68 

Smelters  of 20 

Production  of  zinc  ore 64,  226 

Sheet  zinc 90 

Spelter 71,  72,     73 

Zinc  industry  of 37 

Ore  deposits 175,  208,  226 

Spalling  of  ore 235 

Specific  heat  of  zinc loo 


PAGE 

Specific  gravity  of  minerals 244 

Zinc    134 

Vapor   134 

Zinc  chloride  solutions 166 

Zinc  sulphate  solutions 153 

Spelter,  analysis  of 126,  140 

Combinations   to   regulate   price   of, 

88,  89 

Consumption  of   49 

in  the  United  States 46 

Derivation  of  the  word 2 

Production  in  Russia 36 

Statistics  of  consumption 75 

Price 82 

World's  production 73 

Spirek,  Vicente   6 

Spring,  on  separation  of  lead  and  zinc.  139 

Stahlschmidt,  on  volatility  of  zinc  oxide  157 

Standard  Acid  Co 21 

Steam  boilers,  use  of  zinc  in 55 

Steger,   V.,   on   composition   of   Silesian 

zinc  ore 218 

Steinbeck's  method  of  determining  basic 

sulphates    130 

Sterro's  metal 146 

Stirling,  Lord 190 

Stirling  Hill,  N.  J.,  zinc  mines 178,  190 

Stirling  Iron  &  Zinc  Co 240 

Stolberg,      Germany,     manufacture     of 

brass  at   '.  . .  .  3 

Zinc  works   19 

Stone,   George  C 101 

Straight     Creek,     Tenn.,     zinc     mines, 

178,  197,  199 

Strength  of  zinc 136 

Strontium    133 

Sugar  Orchard  District,  Arkansas 180 

Sulman,  H.  L 138 

Sulman  &  Picard  smelting  process.  .  .  .  230 

Sulphate  of  zinc 61,  153,  173 

Production  of 91 

Sulphates,  assay  methods  for 121,  130 

Sulphide  of  zinc 148,  171 

Sulphide  Corporation,  Ltd 230 

Sulphides,  assay  of 130 

Sulphites  of  zinc 152 

Sulphur,  assay  methods  for 121 

as  impurity  in  spelter 141 

Sulphuric  acid  works  in  Belgium.  .  .17,  25 

at  Oberhaussen,  Westphalia 19 

in  Silesia   18 

Sulphurous  acid,  assay  of 130 

Swansea,  Wales,  smelting  works  at.. 7,  19 

Swansea  Vale  Zinc  Co.,  Illinois 21 

Swansea  Vale  Spelter  Co.,  Wales 19 

Sweden,  production  of  zinc  ore 64 

Zinc  ore  deposits 208,  227 

Swedish  zinc  ore,  composition  of 29 

Sylvester  and  Hobson 136 


Tabb  mine,  Kentucky 182 

Tables  for  ore  concentration 243 

for  ore  sorting 237 

Tailings,  assay  of,  in  Joplin  district.  .  .  251 

Tallow  clay   176 

Tasmania,  zinc  ore  deposits 231 

Tasmanian  Copper  Co 231 

Temperature   attained   in   blende   roast- 
ing      157 

of  dissociation  of  zinc  carbonate...  161 

of  reduction  of  zinc  oxide 157 

Tenda  mine.  Italy 225 

Tennessee,  mining  conditions  in 200 

Production  of  spelter 74 

Zinc  ore 69,  178,  179,  197 

Tensile  strength  of  zinc 136 


INDKX. 


PAGE 

Teruel,   ore  deposits   of 226 

Production  of  zinc  ore 37 

Thallium,  as  impurity  in  spelter.  .  .138,  140 

Theresiahiitte.  Silesia 01 

Thermal  conductivity  of  zinc 136 

Thermochemical     data     of     zinc     com- 
pounds      167 

Thiosulphate  titration  for  zinc 109 

Thiosulphite  of  zinc 152 

Thometzek  distillation  furnace 10 

Thomsen.   thermochemical   data 167 

Thorpe,  on  zinc  carbonate 160 

Thurn,  on  boiling  point  of  zinc 134 

Thurzohiitte.  Silesia 18,  91 

Tin  as  impurity  in  spelter 138,  140 

in  spelter,  determination  of 126 

Tin-zinc  alloys   145 

Titcomb,    H.   A.,    on   mining   at   Joplin, 

Mo 190 

Titration   (see  Assay  Methods). 

Tombac 146 

Topf's  method  of  assaying  zinc  dust.  .  .  129 

Trautwine.  on  strength  of  zinc 137 

Trieuse  magnetic  separator 285 

Trifailer  Kohlenwerksgesellschaft   17 

Troemner  solution  scales 302 

Troost,  on  boiling  point  of  zinc 134 

Troostite   176 

Trzebinia,  Austria,  zinc  works 17 

Tunis,  production  of  zinc  ore 65 

Zinc  deposits 228 

Turkey,  production  of  zinc  ore 65 

Zinc  deposits  of 227 

Turkey  fat  ore 174 

Tuscany,  zinc  mines 223,  225 

Tutenegue,  origin  of  word 2 

Tutanego 2 

Tyrol,  zinc  mines 208 

U 

Udias  mines,  Spain 226 

Ueberoth  mine,  Pennsylvania 195,  196 

United  Kingdom  (see  Great  Britain). 

United  States,  character  of  zinc  ore.  . .  45 

Coal  resources 41 

•  Consumption   of   spelter 46,  80 

Zinc  white 81,  82 

Cost  of  fire  clay 46 

Exports  of  zinc  ore 70 

History  of  zinc  smelting  in 13 

Production  of  spelter 71,  72,  74 

Zinc  ore .' . .  .  69 

Zinc  oxide 75,  81 

Smelters  of   20 

Zinc  industry  of 37 

United  States  Steel  Corporation 47 

United  States  Zinc  Co 21,  47 

United  Zinc  and  Chemical  Co 21 

Unschuld  mine,  Silesia 219 

Unterwindofen  used  in  Silesia 10 

Upland.  Ind.,  smelting  works  at 21 

Upper  Ilarz  (see  Harz  Mountains). 
Upper  Silesia    (see  Silesia). 

Uses  of  zinc 48 

Usine  ii  Zinc  de  St.  Amand 18 

Ujest,  Duke  of 10,  18,  33 

Utah,  zinc  ore  deposits  of 200 


Valentine,  Basil   1 

Valentin-Cocq  smeltery,   Belgium. 6,  17,  23 

Valuation  of  zinc  dust 128 

Zinc  ore 303 

Value    (see  Price  and  Cost). 

of  lead  and  silver  bearing  zinc  ore.  312 

of  zinc  ore.  .               .  .200.  303.  310.  312 


PAOK 

Van  Swab  produces  zinc 3 

Vapart  mill   257 

Vautin  on  use  of  sodium-zinc  alloy 146 

Vezin,  H.  A 299 

Vezin  sampler 298 

Victor  mine,  Missouri 188 

Vieille  Montagne    (see  also  Moresnet). 

3,  4,  209 

Vieille  Montagne,  Soc.  Anon,  de  la.  .5, 
6,  17,  18,  19,  23,  25,  27,  28,  30,  31, 
32,  49,  50,  51,  52,  54,  65,  91,  92, 

214,  220,  227,  228,  256 

Vieille  Montagne  sheet  zinc  gauge 51 

Villiers  Spelter  Co 19 

Violle,  on  boiling  point  of  zinc 134 

Virginia,  coal  resources 38,  41 

Production  of  spelter 16,  74 

Zinc  ore 69 

Zinc  ore  deposits 176,  178,  179,  200 

Vivian  &  Sons 19 

Vivians'  smelting  works 7 

Viviez,  France,  zinc  works  at 18,  30 

Volatility  of  zinc  oxide 157 

Voltz,  Dr.  H 9 

Voltzite    172 

Volumetric  assay  for  cadmium Ill 

Iron   115 

Lead 112 

Lime   118 

Sulphur   123 

Zinc   93 

Zinc  dust 129 

Von  Kobell,  on  acid  sulphate  of  zinc. . .  156 
Von  Schulz  &  Low  method  of  determin- 
ing zinc 95,  99,  111 

Vulcan  Spelter  Co 21 

W 

Wahl,  A.  R.,  on  assay  of  zinc  dust 129 

Wages,  rates  in  Belgium 28 

Germany   31,     33 

Greece   35 

Joplin,  Mo 248 

Silesia    11,  246 

United  States 46 

Wales , 34 

Wales  (see  also  Great  Britain). 

Valuation  of  zinc  ore  in 307 

Walker,  P.  H.,  method  of  zinc  deter- 
mination    108 

Waring,  W.  G.,  on  valuation  of  zinc  ore  310 

Warrington,  England,  zinc  works 19 

Watchmaker's  alloy 146 

Watson,  Bishop 3 

Waukegan,  111.,  smelting  works 21,     41 

Weathering  of  sheet  zinc 137,  162 

Webb  City,  Mo.,  ore  dressing  at 250 

Zinc  mines 183,  185,  187 

Weight  of  sheet  zinc 50,     51 

Weiller,    on   electrical    conductivity    of 

zinc  136 

Weir,  John,  Lead  &  Zinc  Co 198,  199 

Weir,  Kan.,  zinc  works  at 15,     21 

Welkenrodt.  Belgium,  zinc  mines 210 

Welsh-Belgian  method  of  smelting 23 

Wenona  Zinc  Co.,  Illinois 21 

Wenstrom  magnetic  separator 266,  268 

Werren,  on  action  of  acids  on  zinc. . . .   137 

Wertheim,  on  strength  of  zinc 136 

Westphalia,  coal  resources 31 

Cost  of  coal 31 

Smelters 19,     30 

Zinc  deposits 220 

Production   16 

West  Virginia,  natural  gas 45 

Wessola.  Silesia,  first  zinc  smelting  at.       8 


328 


INDEX. 


Wetherill,  J.  P .  278 

Process  of  magnetic  separation. .  268,  269 

Wetherill,  Samuel   14 

Wetherill   process   of  magnetic  separa- 
tion   15 

of  making  zinc  oxide 15 

Wetherill  magnetic  separators.  .37,  70, 

174,  181,  259,  269,  279 

Wetherill  Separating  Co 269 

Wharton,  Joseph 14 

White  bronze 58 

Whitney,  J.  D 14,  195 

Wiedemann,  on  thermal  conductivity  of 

zinc   136 

Wiesloch,  Baden,  zinc  ore  at 174,  212 

Wilder's  metal  coating 147 

Wilfley  table 181,  243,  248,  278,  250 

Wilhelminehutte,  Silesia 9,  10,  18,  91 

Wilkens,  H.   A.  J 273,  275 

Willemite 176 

Magnetic  separation  from  franklin- 

ite 267 

Williams,  Foster  &  Co 19 

Windisch-Bleiberg,  Austria,  zinc  mines.  208 

Winnington,  England,  zinc  works 19 

Winslow,  Arthur 188 

on  Joplin  ore  deposits 189,  190 

on  zinc  ore  production  in  Wisconsin  204 

Wisconsin,  ore  deposits 178,  179,  203 

Practice   in    separating   blende   and 

pyrite 256 

Production  of  zinc  ore 70,  204 

Zinc  mines 14 

Wisconsin  Lead  &  Zinc  Co 256 

World's  production  of  spelter 71,  73 

Wurtz,  on  melting  point  of  zinc 134 

Wurtzite 172 

Wyoming  coal  field 41 

Wythe  Lead  &  Zinc  Co 20,  200,  276 

Wytheville,  Va.,  smelting  works 20 


Zaghouan  mines,  Tunis > 229 

Zawodzie,  Silesia,  smelting  works 18 


PAGE 

Zenith  mine,  Ontario 205 

Zevel,  Arnold  van 3 

Zinc,  action  of  acids  on '.  137 

Alloys   141 

Amalgams   '.[',[  145 

Atomic  weight   133 

Castings   55 

Chemical  compounds  (see  Oxide,  Sul- 
phide, etc.). 

Determination  of 93 

Eastern  origin  of 2,  3 

Effect  of  impurities 138 

Impurities  in   135 

in  by-products  from  iron  smelting.  .  219 

in  lead  smelting  slags 149 

Microscopical  examination 139 

Occurrence  of  native 177 

Physical  properties 134 

Production  in  Silesia 67 

Use  in  desilverizing  lead 147 

in  cyanide  process 56 

in  galvanizing   60 

to  prevent  boiler  corrosion 55 

Vapor,  specific  gravity  of 134 

Zinc  dust   ...... 57,  60 

Assay  of 128 

Combustibility  of 135 

Production   72,  90 

Zinc  ore 169 

Average  price  at  Joplin 89,  90 

Impurities  in 290 

Production  of  Joplin  district 188 

in  New  Jersey 194 

Valuation  of 303 

Value  of 290 

Affected  by  lead  and  iron. .  .310,  312 
Zinc  oxide   (see  also  Oxide  of  Zinc). 

Manufacture  in  New  Jersey 13 

Zinc  sulphate  manufacture  at  Goslar. . .  138 
Zinc  white   (see  Zinc  Oxide). 

Zinkiferous  clay   188,  201 

Zinkite 175 

Zinkmaatshappy  in  Limburg 20 


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Rock-forming     Minerals    and 

Rocks. 
Physical  Character  of  Mineral 

Deposits. 
Origin  of  Veins. 
Filling  of  Mineral  Veins. 
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Filling. 
Mineral  Deposits  Other  than 

Veins. 
Prospecting. 


III. 
IV. 

V. 

VI. 

VII. 

VIII. 
IX. 


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CHAPTER   III. — Magnetic   and   Pyrite. 

CHAPTER  IV. — Copper. 

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CHAPTER  VIII.— Lead  and  Silver. 

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and  Colorado. 

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Arizona  and  Nevada. 

CHAPTER  XII.— The  Pacific  Slope— Wash- 
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CHAPTER  XIII. — Gold  Elsewhere  in  the 
United  States  and  Canada. 

CHAPTER  XIV.— The  Lesser  Metals— Alum- 
inum, Antimony,  Arsenic,  Bismuth, 
Chromium,  Manganese. 

CHAPTER  XV.— The  Lesser  Metals,  Con- 
tinued— Mercury,  Nickel  and  Cobalt, 
Platinum,  Tin. 

CHAPTER  XVI. — Concluding  Remarks. 

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